Design, Synthesis, and Self-assembly of Well-defined Hybrid Materials Including Polymer Amphiphiles and Giant Tetrahedra Molecules Based on POSS Nanoparticles

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ISBN 13 :
Total Pages : 220 pages
Book Rating : 4.:/5 (14 download)

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Book Synopsis Design, Synthesis, and Self-assembly of Well-defined Hybrid Materials Including Polymer Amphiphiles and Giant Tetrahedra Molecules Based on POSS Nanoparticles by : Mingjun Huang

Download or read book Design, Synthesis, and Self-assembly of Well-defined Hybrid Materials Including Polymer Amphiphiles and Giant Tetrahedra Molecules Based on POSS Nanoparticles written by Mingjun Huang and published by . This book was released on 2015 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Bottom-up" techniques-based self-assembly are always attracting people's interests since this technology provides relatively low economic cost and fast route to construct organized structures at different scales. Considering unprecedented benefits from polymer materials, self-assemblies utilizing polymer building blocks have been extensively studied to achieve diverse hierarchical structures and various attractive properties. However, precise controls of chemical primary structures and compositions and exact constructions of hierarchal ordered structures in synthetic polymers are far from being fully appreciated. In this dissertation, a novel approach has been utilized to construct diverse well-defined nano-building blocks, giant molecules, via conjugating different, and functionalized molecular nanoparticles (MNPs) which are shape- and volume-persistent nano-objects with precise molecular structure and specific symmetry. The representative examples of the three basic categories of giant molecules, "giant polyhedra", "giant surfactants", and "giant shape amphiphiles" were discussed in details. First, a class of precisely defined, nanosized giant tetrahedra was constructed by placing different polyhedral oligomeric silsesquioxane (POSS) molecular nanoparticles at the vertices of a rigid tetrahedral framework. Designed symmetry breaking of these giant tetrahedra introduces accurate positional interactions and results in diverse selectively assembled, highly ordered supramolecular lattices including a Frank-Kasper (FK) A15 phase. The FK and quasicrystal phases are originally identified in metal alloys and only sporadically observed in soft matters. It remains unclear how to correlate their stability with the chemical composition and molecular topology in the self-assembling systems. We then for this purpose designed and studied the self-assembly phase transition sequences of four series of hybrid giant surfactants based on hydrophilic POSS cages tethered with one to four polystyrene (PS) tails. With increasing the number of tails, molecular topological variations not only affect phase boundaries in terms of the PS volume fraction, but also open a window to stabilize supramolecular FK and quasicrystal phases in the spherical phase region, demonstrating the critical role of molecular topology in dictating the formation of unconventional supramolecular lattices of "soft" spherical motifs. The FK A15 phase was even surprisingly observed in the giant shape amphiphile molecule, triphenylene-6BPOSS, which has a disk-like flat triphenylene core connected with six hydrophobic POSS cages by sides. Without conical molecular shape, triphenylene-6BPOSS self-assembled and stabilized into supramolecular sphere via p-p interactions through a completely different mechanism with precious two cases. These studies indicate that "bottom-up" self-assemble based on well-defined giant molecules approach can be rather powerful to fabricate usually complicated hierarchical structures and open up a wide field of supramolecular self-assembly with unexpected structure and properties.

Design, Synthesis and Self-assembly of Giant Molecules, Including Giant Surfactants and Giant Tetrahedrons Based on POSS Nanoparticles

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Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)

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Book Synopsis Design, Synthesis and Self-assembly of Giant Molecules, Including Giant Surfactants and Giant Tetrahedrons Based on POSS Nanoparticles by : Wenpeng Shan

Download or read book Design, Synthesis and Self-assembly of Giant Molecules, Including Giant Surfactants and Giant Tetrahedrons Based on POSS Nanoparticles written by Wenpeng Shan and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The self-assemble behavior of various giant surfactants with different functionalities and molecular architectures, which consist of compact and rigid molecular nanoparticles (MNPs) as head and flexible polymer chains as tail, is systematically studied. The benefit of utilizing MNPs comparing with AB type di-block copolymer which has become the model for probing microphase separation in bulk state is that the MNPs could be versatile functionalized at will to fabricate functional materials via collective secondary interactions. Herein, we investigated the effect of rigid-rod junction between two blocks of giant surfactants in bulk state using small angle X-ray scattering and transmission electron microscopy. Besides the segmental interaction (x, Flory-Huggins parameter) and volume fraction of one component (f), the interfacial energy takes a vital role in the process of self-assembly. By way of about 1 nm rigid-rod junction inserted into the giant surfactant system, the pathways of order-order phase transition (OOT) could be varied due to different molecular weight of polystyrene attached inducing diverse levels of gibbs free energy with temperature increasing, one proceeds from lamellar structure (LAM) directly to the hexagonally packed cylinder structure (CYL), one passes by the double gyroid structure (DG), another one travels from LAM to hexagonally perforated layer structure (HPL), then DG, finally reaches to the stable state, CYL that possesses the most curved interfacial area in these previous mentioned structures. And the model which describes these sorts of phase behaviors with interfacial tension and packing frustration competing each other could be verified via the phenomena that curved lamellar defects observed both in bright field TEM image and small angle x-ray scattering data, which could be occurred due to the relaxation of polymer chains promoting the increase of interfacial area without loosening the imbalance of chain crowding because of tightly packed MNPs to stimulate the OOT. This prototype of phase transition supporting a fully described phase diagram provides clues to control polymer self-assembly and fine-tune the morphology and phase behaviors at the nanometer scales. In the second topic, the giant tetrahedron was fabricated on the adamantane core, same as the mechanisms of disk shape molecules forming spherical phase structures, the steric hindrance from POSS cages impeded the growth of cylindrical columns, and spherical phase structures could be achieved based on the experimental data of BCC structure appearing. And this type of fabricating spherical phase structures could pave another road to get Frank-Kasper phases with different sizes of spheres.

Design, Synthesis and Self-assembly of Polyhedral Oligomeric Silsesquioxane (POSS) Based Hybrid Materials

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ISBN 13 :
Total Pages : 139 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Design, Synthesis and Self-assembly of Polyhedral Oligomeric Silsesquioxane (POSS) Based Hybrid Materials by : Ni Bo

Download or read book Design, Synthesis and Self-assembly of Polyhedral Oligomeric Silsesquioxane (POSS) Based Hybrid Materials written by Ni Bo and published by . This book was released on 2018 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: The giant molecules systems exhibit very interesting behaviors in the supramolecular assemblies over the past several years compared to other macromolecular systems. As an old Chinese saying goes "good tools are prerequisites for a successful execution of a job". This dissertation focuses on the synthetic possibilities based on the previous work and try to explore some progress in the first part. The second part of the dissertation encapsulates the self-assembly behaviors of the synthesized giant molecular systems. A pre-functionalization method was developed to achieve giant molecular families with more abundant functionalities. Fluorinated polyhedral oligomeric silsesquioxane (FPOSS), long alkyl chain functionalized POSS (C8POSS), and protected carboxylic acid group functionalized POSS (tAPOSS) were designed and prepared. These kinds of molecules are viewed as molecular nanoparticles (MNPs). The reactivities of the modules was proved by combining them with polymer systems like polystyrene via "click" chemistry. These precisely defined functionalized POSS-containing hybrids could serve as model molecules to investigate the self-assembly behaviors of giant molecules.The solution self-assembly of a giant surfactant consisting of a polystyrene-block-poly (ethylene oxide) (PS-b-PEO) diblock copolymer tail tethered onto a fluorinated polyhedral oligomeric silsesquioxane (FPOSS) cage in 1,4-dioxane/water was investigated. Abundant unconventional micellar structures including toroids, two-dimensional hexagonally patterned colloidal nanosheets, and laterally structured vesicles were observed.2 This study not only exhibits various unique morphologies, but also promotes the fundamental understanding on the pathways of the transformations between different morphologies in the solution self-assembly behavior of giant surfactants.In the MNPs and polymer hybrid systems, the MNPs were with precise molecular weights and chemical compositions. But the polymers used still have a molecular weight distribution which originates from the nature of the polymerization methods applied. To eliminate the polydispersity effect from the system, it is crucial to have molecular systems with precise molecular weights and chemical structures from the physical point of view. Upon this anticipation, we have designed a series of dendrons which are compositionally identical, but their linkers are in different chemical connection geometries. These sets of macromolecules are composed of hydroxyl group functionalized POSS (DPOSS) and isobutyl functionalized POSS (BPOSS). The final dendron structure consists of three parts, one DPOSS at the apex, four BPOSSs at the periphery and the flexible linkers. Note that this series of dendrons is topological isomers. Self-assembled structures of four dendron topological isomers were studied using SAXS and TEM. The results help us to understand the role of linkers in a amphiphiles system and give us some guidance on how to design a molecular system in the future.

Polymer/POSS Nanocomposites and Hybrid Materials

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Publisher : Springer
ISBN 13 : 3030023273
Total Pages : 462 pages
Book Rating : 4.0/5 (3 download)

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Book Synopsis Polymer/POSS Nanocomposites and Hybrid Materials by : Susheel Kalia

Download or read book Polymer/POSS Nanocomposites and Hybrid Materials written by Susheel Kalia and published by Springer. This book was released on 2018-11-27 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview of polymer nanocomposites and hybrid materials with polyhedral oligomeric silsesquioxanes (POSS). Among inorganic nanoparticles, functionalized POSS are unique nano-building blocks that can be used to create a wide variety of hybrid and composite materials, where precise control of nanostructures and properties is required. This book describes the influence of incorporation of POSS moieties into (organic) polymer matrices on the mechanical, thermal and flammability behavior of composites and hybrid organic-inorganic materials. Importantly, POSS-containing materials can be bio-functionalized by linking e.g. peptides and growth factors through appropriate surface modification in order to enhance the haemo-compatibility of cardiovascular devices made of these materials. This volume includes descriptions of synthesis routes of POSS and POSS-containing polymeric materials (e.g. based on polyolefines, epoxy resins and polyurethanes), presentation of POSS’ role as flame retardants and as biocompatible linker, as well as the depiction of decomposition and ageing processes.

Polymer and Polymer-Hybrid Nanoparticles

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Publisher : CRC Press
ISBN 13 : 1439869073
Total Pages : 504 pages
Book Rating : 4.4/5 (398 download)

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Book Synopsis Polymer and Polymer-Hybrid Nanoparticles by : Stanislav Rangelov

Download or read book Polymer and Polymer-Hybrid Nanoparticles written by Stanislav Rangelov and published by CRC Press. This book was released on 2013-08-28 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymeric and hybrid nanoparticles have received increased scientific interest in terms of basic research as well as commercial applications, promising a variety of uses for nanostructures in fields including bionanotechnology and medicine. Condensing the relevant research into a comprehensive reference, Polymer and Polymer-Hybrid Nanoparticles: From Synthesis to Biomedical Applications covers an array of topics from synthetic procedures and macromolecular design to possible biomedical applications of nanoparticles and materials based on original and unique polymers. The book presents a well-rounded picture of objects ranging from simple polymeric micelles to complex hybrid polymer-based nanostructures, detailing synthetic procedures, techniques for characterization and analysis, properties, and behavior in selective solvents and dispersions. Each chapter contains background and introductory information, summarizing generalities on the nanosystems being discussed. The chapters also describe representative works of experts and provide in-depth, focused discussions. The authors present current knowledge on the following topics: Designed synthesis of functional polymers Construction of block copolymer micellar and nonmicellar self-assembled structures Construction of organic–organic hybrid nanosized particles Construction of organic–inorganic hybrid nanoparticles and nanoassemblies The final chapter addresses biological applications of polymeric nanoparticles, including delivery of low-molecular-weight drugs, macromolecular drugs, imaging and diagnostics, and photodynamic therapy. Summarizing important developments in the field, the authors condense relevant research into a comprehensive resource.

Design, Synthesis and Self-assembly of Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxane-polymer Conjugates

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ISBN 13 :
Total Pages : 225 pages
Book Rating : 4.:/5 (129 download)

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Book Synopsis Design, Synthesis and Self-assembly of Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxane-polymer Conjugates by : Kan Yue

Download or read book Design, Synthesis and Self-assembly of Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxane-polymer Conjugates written by Kan Yue and published by . This book was released on 2013 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hierarchally ordered supramolecular structures generated by self-assembly of various nano-materials have attracted great amount of interests due to their potentials in advanced material designs and applications via the "bottom-up" approach. In the field of polymer science, studies on block copolymers and their well-documented micro-phase separation behaviors have been one of the central themes during the past a few decades. The consequentially proposed block copolymer lithography based on these studies is considered as one of alternative solutions to complement the traditional photolithography and further reduce the feature sizes of microelectronic fabrications. However, it is still a grand challenge to achieve micro-phase separated ordered structures with sub-20 nm feature sizes in common block copolymer systems, as well as to obtain unconventional self-assembled ordered phases. It replies on the development of novel materials to resolve these problems. "Shape amphiphiles", constructed by the chemical integration of molecular nano-building blocks with distinct shapes and competing interactions, emerge as a novel class of nano-materials. In this dissertation, the molecular design and synthesis of a library of shape amphiphiles with precisely defined structures based on conjugates of functionalized polyhedral oligomeric silsesquioxanes (POSS) and polystyrene (PS) are presented. These POSS-PS conjugates capture the structural features of small molecule surfactants but represent their size-amplified analogues and are thus, also referred as "giant surfactants". The development of a "sequential click approach" and the utilization of a series of "click adaptor molecules" facilitated the modular and efficient precision synthesis and the feasible structural diversification of molecular architectures for a systematic investigation. It was subsequently revealed that in the bulk state, driven by the nano-phase separation between the functionalized POSS cages and the polymer chains, POSS-based shape amphiphiles can self-assemble into various kinds of ordered supramolecular phases depending on the relative volume fraction of the two components and the molecular topology. The unique structural features of POSS-based shape amphiphiles, such as the shape persistence of the POSS cages and the high x value due to the clustering of functional groups, resulted in an asymmetric phase diagram of ordered structures with sub-10 nm feature sizes. Moreover, self-assembly of these shape amphiphiles exhibited a remarkable sensitivity on the molecular architectures, which resembles the properties of small molecule surfactants rather than the block copolymers. By tuning the molecular architectures, some exceptional phases could be observed, such as an inversed honeycomb phase and a highly asymmetric lamellar phase, as observed in the multi-headed giant surfactant system. Therefore, it is concluded that POSS-based shape amphiphiles provide a versatile platform for advancing our understanding about the self-assembled diverse equilibrium phase structures with sub-20 nm feature sizes.

Synthesis and Self-assembly of Molecular Shape Amphiphiles

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ISBN 13 :
Total Pages : 176 pages
Book Rating : 4.:/5 (124 download)

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Book Synopsis Synthesis and Self-assembly of Molecular Shape Amphiphiles by : Xinfei Yu

Download or read book Synthesis and Self-assembly of Molecular Shape Amphiphiles written by Xinfei Yu and published by . This book was released on 2012 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer-tethered nanoparticles are one kind of shape amphiphiles, which are geometric objects with distinct shapes and chemical functionalities. Hydrophilic polyhedral oligomeric silsesquioxane (POSS) and fullerene (C60) are utilized as model nanoparticles while hydrophobic polystyrene (PS) chains are used as tetheres to construct model molecular shape amphiphiles.PS-tethered carboxylic acid functionalized POSS with different PS chain lengths, PSN-APOSS, were synthesized by combining anionic polymerization and thiol-ene "click" chemistry. PSN-APOSS formed micelles in selective solvents which were studied by transmission electron microscopy (TEM) and light scattering (LS) experiments. The effects of PS chain length, common solvents, and solvent/nonsolvent ratio on the micellar morphologies of PSN-APOSS have been investigated. The multivalent interactions between APOSS cages with fixed shape and volume made the self-assembly behaviors of PSN-APOSS distinct from those of traditional amphiphilic block copolymers. The self-assembled ordered structures of PSN-APOSS in the condensed state were studied by small angle X-ray scattering (SAXS) and TEM experiments. The ordered structures changed from lamellae, to hexagonal packed cylinders, and to body-centered cubic spheres as increasing PS chain length. The size of self-assembled structure is around 10 nm, which is challenging for traditional diblock copolymers. 1,3-Dipolar Huisgen cycloaddition of alkyne-azide "click" reaction was utilized to synthesize the PS mono- and di-tethered hydrophilic C60 (PSN-AC60 and 2PSN-AC60) with well-controlled topology and various PS chain lengths. Self-assembled aggregates (micelles and colloidal particles) of these shape amphiphiles were prepared in solutions and studied by TEM and LS experiments. A systematic morphological phase diagram for PSN-AC60 was obtained depending on the molecular concentration, PS chain length, and solvent composition. Concentration-sensitive self-assembled morphologies were ascribed to multivalent interactions between AC60 nanoparticles as well as the PS chain stretching. The topology effect on the formation of both micelles and colloidal particles was revealed by PS44-AC60 and 2PS2323-AC60, which have identical PS weight fractions. These giant molecular shape amphiphiles thus represent a novel class of amphiphilic molecules that have not been systematically explored beyond the traditional surfactants and block copolymers systems, which provide a new platform for understanding supramolecular self-assemblies of amphiphilic molecules in solution and in condensed state.

Design, Synthesis, and Self-assembly of Giant Shape Amphiphiles with Precisely Controlled Compositions, Interactions, and Geometries Via a Molecular Lego Approach

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ISBN 13 :
Total Pages : 194 pages
Book Rating : 4.:/5 (126 download)

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Book Synopsis Design, Synthesis, and Self-assembly of Giant Shape Amphiphiles with Precisely Controlled Compositions, Interactions, and Geometries Via a Molecular Lego Approach by : Su Zebin

Download or read book Design, Synthesis, and Self-assembly of Giant Shape Amphiphiles with Precisely Controlled Compositions, Interactions, and Geometries Via a Molecular Lego Approach written by Su Zebin and published by . This book was released on 2019 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assemblies of soft matters attract broad interests of material scientists since this technology provides versatile designs, relatively low economic cost, convenient route to construct ordered structures at different scales. Tremendous achievements such as various of hierarchical architectures and diverse attracting properties have been achieved by utilizing by self-assemblies of polymer building blocks. However, the challenges of precise controls of designed chemical primary structures, compositions, molecular topology and exact constructions of assembled structures in synthetic polymers are far away from being well addressed. In this dissertation, a novel approach named "molecular Lego approach" has been utilized to construct various well-defined giant molecules, constructed by several types of building blocks, which are nano-sized molecules with precise molecular structure, relatively rigid conformation, and defined molecular symmetry. Three categories of "giant shape amphiphiles" with different driving force for self-assemblies were designed, synthesized, and investigate in detail. First, we designed and synthesized a series of nanosized giant shape amphiphiles in which a triphenylene core is attached to six identical polyhedral oligomeric silsesquioxane (POSS) cages at the periphery through covalent linkers with tunable lengths. Giant shape amphiphiles are molecular building blocks that consist of different moieties of distinct shapes, and engage in competing interactions. The relatively weak [pi-pi] stacking interactions among conjugated aromatic triphenylene cores enable the segregation from peripheric BPOSS cages (POSS functionalized with seven isobutyl groups). Moreover, the tunability of the linker length enables the formation of various ordered spherical phases. Using this platform, we report the experimental observation of the FK Z phase in a soft matter system. Based on these results, we then designed and studied the self-assembly phase transition behaviors of another two series of giant shape amphiphiles. The driving force of these two series of giant shape amphiphiles are only [pi-pi] stacking interactions supplied by triphenylene core, but also hydrogen bonding supplied by the linkers. With systematically tuning the length and rigidity of the linkers, we observed various of phases, including DDQC phase, F-K [sigma] phase, body centered cubic (BCC) phase and HEX phase. Furthermore, we find two sets of giant shape amphiphiles based on benzene-1,3,5-tricarboxamide and cyclotriphosphazene. There is not [pi-pi] stacking interaction between these two types of cores. The driving force for these two sets of samples are mainly hydrogen bonding. These two sets of giant shape amphiphiles self-assemble into BCC phase and A15 phase. These results suggest that the crown shape molecular design is a general way to construct complex spherical phases. These studies suggest that "molecular Lego approach" self-assemblies based on well-defined giant shape amphiphiles can be a powerful platform for achieving unconventional hierarchical structures and pave a new way for supramolecular self-assembly with expected structure, designed properties and function.

Synthesis and Self-assembly of Star-shape Giant Molecules Based on Hydrophilic Polyhedral Oligomeric Silsesquioxane (POSS)

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (17 download)

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Book Synopsis Synthesis and Self-assembly of Star-shape Giant Molecules Based on Hydrophilic Polyhedral Oligomeric Silsesquioxane (POSS) by : Gaoyan Mu

Download or read book Synthesis and Self-assembly of Star-shape Giant Molecules Based on Hydrophilic Polyhedral Oligomeric Silsesquioxane (POSS) written by Gaoyan Mu and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemical and physical properties of materials are determined not only by composition but also hierarchical structures. Hierarchical structures are formed by "bottom up" method, self-assembly of nano-scale building blocks into supramolecular assemblies via secondary interactions.1 In recent years, a series of functionalized POSS were utilized as "nanoatoms" to synthesize well-defined giant molecules. As a kind of giant molecules, giant surfactants are focused in my work. To investigate the fundamental principles of self-assembly, the giant surfactants with precise molecular structures have been synthesized by clicking "nanoatoms" to flexible polymer tails with controlled molecular weight. Because the self-assemblies of giant surfactants are sensitive to topological structures, a series of "giant surfactant" with multi-heads or multi-tails have been synthesized.2 In my work, the APOSS based star-shape giant molecules with or without polystyrene (PS) tails were precisely synthesized via "living" radical polymerization and "click chemistry". The chemical structure of the product was confirmed by 1H NMR spectrum, 13C NMR spectrum, GPC spectra, FT-IR spectra and MALDI-TOF mass spectra. After the self-assembly of samples in solution, the structures formed were investigated by transmission electron microscopy (TEM), static light scattering (SLS) and dynamic light scattering (DLS).

Giant Molecular Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxanes: Molecular Design, "click" Synthesis and Self-assembly

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Book Synopsis Giant Molecular Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxanes: Molecular Design, "click" Synthesis and Self-assembly by : Yiwen Li (Chemist)

Download or read book Giant Molecular Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxanes: Molecular Design, "click" Synthesis and Self-assembly written by Yiwen Li (Chemist) and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emergence of giant molecular shape amphiphiles as important building blocks for "bottom-up" nanofabrication has sparked substantial interest because conformation rigidity and shape anisotropy provide additional factors in directing self-assembly into various hierarchical structures. It has been found that giant molecular shape amphiphiles are able to self-assemble into diverse hierarchical supramolecular structures, similar to those observed in small molecular amphiphiles and block copolymers; yet this class of amphiphiles possesses distinct differences with various molecular shape, symmetries, and topologies. The purpose of this research is to develop several kinds of Polyhedral Oligomeric Silsesquioxanes (POSS)-based giant molecular shape amphiphiles with precisely defined molecular structures and functionalities by using thiol-ene "click" chemistry and other precise transformations. To achieve this, a library of monofunctional vinyl POSS building blocks with C3V symmetry was firstly prepared in good yields, which could serve as important precursors for further design and synthesis of various POSS-based giant molecular shape amphiphiles. The supramolecualr structures of these assemblies along with the resulting ordered structures are also fully investigated to determine their structure-property relationships. Functionalized POSS cages with different surface chemistry and size were employed to construct dumbbell- and snowman-like molecular Janus particles with various symmetry breakings. The self-assembly of dumbbell-like Janus particles leads to the formation of hierarchically ordered supramolecular structures in bulk. While the ordered packing of POSS within each layer is lost upon heating via undergoing through a first order transition, the bi-layered structure persists up to the decomposition temperature. The driving force of the hierarchical structure formation was attributed to the free energy minimization via the pathway guided by the symmetry breaking in both geometrical sense and chemical sense. Another illustrating example is a series of novel functional POSS heads tethered polymer tails-based giant molecular shape amphiphiles including giant surfactants, lipids, gemini surfactants and miktoarm shape amphiphiles. Diverse architectures of this class of materials have been constructed using sequential "click" chemistry and their self-assembly processes in solution have also been fully discussed. This set of research results not only opens a new pathway for achieving supramolecular self-assemblies of POSS-based giant molecular shape amphiphiles, but also creates unique materials for developing advanced technologies by combining the properties of those hybrid materials.

Giant Molecular Shape Amphiphiles Based on Hydrophilic [60]fullerene with Asymmetric Polymeric Tails

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ISBN 13 :
Total Pages : 56 pages
Book Rating : 4.:/5 (883 download)

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Book Synopsis Giant Molecular Shape Amphiphiles Based on Hydrophilic [60]fullerene with Asymmetric Polymeric Tails by : Pengtao Lu

Download or read book Giant Molecular Shape Amphiphiles Based on Hydrophilic [60]fullerene with Asymmetric Polymeric Tails written by Pengtao Lu and published by . This book was released on 2014 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Inspired by nature, self-assembly, a "bottom up" approach, is now a well-established method to design and develop new materials. It was not until recently that the anisotropy and rigidity of the shape of nanobuilding blocks are also recognized as important parameters in the fine-tuning of self-assembled structures. "Shape amphiphiles", an entity combined by nanobuilding blocks which have distinct chemical properties and anisotropic geometries, thus got much attention from scientists in different fields, because shape amphiphiles can provide new opportunities to engineer materials possessing specific functionalities and physical properties dictated by unique packing of these novel building blocks. However, many previous researches only focused on shape amphiphiles made up of inorganic nanocrystals, while the potential of molecular shape amphiphiles between 1 to 10nms has not been explored yet. In my research, I will focus on one kind of shape amphiphiles in particular -- the attachment of diverse tails to the building blocks at precise positions. Specifically, this kind of shape amphiphiles is based on hydrophilic [60]fullerene and two polymeric tails with different chemical compositions. The synthetic strategy involved is a combination of Bingel-Hirsch reaction and controlled radical polymerization. The former one gives rice to efficient [60]fullerene surface functionalization, while the later one leads to precise control of the length of the polymeric tails. "Click philosophy", which found tremendous applications in synthesizing soft materials possessing well-defined structures in recent years, is also involved. The self-assembled structures of prepared asymmetric shape amphiphiles in solution will be thoroughly investigated by characterization tools, such as TEM (Transmission Electron Microscopy) and DLS (Dynamic Light Scattering), both in solution.

Self-assembly and Folding

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ISBN 13 :
Total Pages : 123 pages
Book Rating : 4.:/5 (815 download)

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Book Synopsis Self-assembly and Folding by : Jacob P. Dumbleton

Download or read book Self-assembly and Folding written by Jacob P. Dumbleton and published by . This book was released on 2012 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Reported are the studies of the self-assembly and polymerization of nanotubes derived from L-lysine based amphiphiles and the synthesis of an azobenzene phosphoramidite catalyst. One dimensional (1D) assembled nanoscale molecules are of particular interest due to the development of optoelectronic nanodevices. While there are many examples of molecular self-assembly of defined nanostructures, there are few that exploit the functionalization with polymeric motifs. Polymerization of defined nanostructures has been shown to improve structural elements as well as allow for the versatility of polymer chemistry to design hybrid materials. Our design focuses on a series of naphthalene diimide (NDI) substituted L-lysine derivatives functionalized at the terminus with strained groups capable of undergoing polymerization. Self-assembly of these systems are induced from the amphiphilicity derived from the hydrophobic and hydrophilic interactions of the molecule, as well as stabilization of the NDI core through long range [pai]-[pai] interactions. Aqueous ring opening metathesis polymerization (ROMP) was performed on these self assembled systems using Grubb's 1st and 2nd generation catalysts. The studies reveal that a stable polymer nanotube is achieved after aqueous polymerization. This polymer becomes disturbed upon the addition of an organic solvent and is no longer capable of adopting a helical structure when re introduced into water. Co-self-assembly studies were performed with a bolaamphiphile known to assemble into discrete tubular structures and an achiral C3 symmetric discotic observed to assemble in aqueous media. Samples were mixed at various concentrations in attempts to elucidate successful chirality transfer from the nanotube to the discotic. UV and CD spectroscopy were used to investigate if self-assembly had occurred. Lastly, a phosphoramidite catalyst was proposed exploiting the folding nature of an azobenzene oligomer. Since it is known that axial chirality in phosphoramidites can be derived from diols such as BINOL and TADDOL, an achiral azobenzene oligomer was designed to investigate if the dynamic chirality of the oligomer can control asymmetric catalysis. The oligomer design is derived from the meta- connectivity of the aromatic groups that forces the molecule to adopt a folded state stabilized through hydrogen bonding and [pai]-[pai] stacking. Incorporation of the azobenzene moieties allows for the potential to control catalysis photochemically.

Synthesis and Self-assembly of Giant Shape Amphiphiles Based on Rod-like Polymers and Precisely Functionalized Fullerenes

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ISBN 13 :
Total Pages : 41 pages
Book Rating : 4.:/5 (128 download)

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Book Synopsis Synthesis and Self-assembly of Giant Shape Amphiphiles Based on Rod-like Polymers and Precisely Functionalized Fullerenes by : Xing Yang (Chemist)

Download or read book Synthesis and Self-assembly of Giant Shape Amphiphiles Based on Rod-like Polymers and Precisely Functionalized Fullerenes written by Xing Yang (Chemist) and published by . This book was released on 2017 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembly is a hot phenomenon these years that many scientists focus. It is a spontaneously process that components in a system assemble themselves to get a larger functional unit. As the technological advancements increasing, the nanometer scale study of materials is going to become more and more important. A wide variety of materials can be built because of the increasingly complex structures which we get from self-assembled nanoparticles. They can be used for different purposes. One of the self-assembly particle is shape amphiphiles. Shape amphiphiles are based on competing interactions and molecular segments of distinct shapes. While computer simulation has predicted intriguing self-assembly behaviors of shape amphiphiles, experimental investigation is largely unexplored. My research will be focusing on the synthesis of a precisely defined shape amphiphiles based on functionalized fullerenes (C60) and rod-like polyfluorene, where the two different types of functionalized C60 will be placed at the two ends of polyfluorene. Also the assembly of as-synthesized shape amphiphiles in solution has been systematically studied. And a novel 'caterpillar' structure has been observed in TEM image.

Design, Synthesis and Self-assembly of Giant Molecules with Precisely Controlled Heterogeneities, Including Composition, Functionality, Topology and Sequence

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Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (981 download)

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Book Synopsis Design, Synthesis and Self-assembly of Giant Molecules with Precisely Controlled Heterogeneities, Including Composition, Functionality, Topology and Sequence by : Wei Zhang

Download or read book Design, Synthesis and Self-assembly of Giant Molecules with Precisely Controlled Heterogeneities, Including Composition, Functionality, Topology and Sequence written by Wei Zhang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In biological systems, it is well-known that the activity and function of biomacromolecules are dictated not only by their primary chemical structures, but also by their secondary, tertiary and quaternary hierarchical structures. Achieving similar levels of control in synthetic macromolecules has yet to be demonstrated. In 1960, Feynman raised a fundamental question: "What would the properties of materials be if we could really arrange the atoms the way we want them?" It is difficult to answer this question at truly atomic level. However, by taking the advantage of the unique giant molecular system recently developed by our group, we are trying to answer it at the "nanoatom" length scale in this dissertation. We started with design, syntheses and crystal structure analyses of three series dyads of sphere-plate giant shape amphiphiles with distinct shapes and precise chemical linkages based on C60-triphenylene (sphere-triangle), C60-perylene diimide (sphere-rectangle) and C60-Porphyrin (sphere-square). We then developed a novel synthetic methodology using orthogonal "click" chemistries, strain-promoted azide-alkyne cycloaddition (SPAAC), oxime ligation and thiol-ene click coupling (TECC), for preparing a library of polystyrene (PS)-polyhedral oligomeric silsesquioxane (POSS) giant surfactants with precisely arranged nano-building blocks. The heterogeneity of primary chemical structure can be precisely controlled and is reflected in the self-assembled supramolecular structures in bulk or in solution. The composition (the volume fraction of hydrophilic "nanoatoms") and functionality are the crucial to determine the assembled structures, illustrated by a series of linear configured PSm-(XPOSS)n. The functionality and topology are also found to affect the assembled structures when the volume fractions are identical, demonstrated by several linear and branched PSm-(XPOSS)n giant surfactants. Furthermore, the sequence effect is explored by comparing the self-assembly behaviors of a pair of sequence isomers. In order to step further answering Feynman's inquire, we extend the synthetic method to prepare truly precise "nanoatom" chains or dendrimers with polydispersity Đ equal to 1, which also form varies order supramolecular structures as we tune their primary chemical structures. Our work offers a promising opportunities to manipulate the hierarchical heterogeneities of giant molecules via precise and modular assemblies of various nano-building blocks, and provides a platform for making precise nanostructures that are not only scientific intriguing but also technologically relevant.

Anionic Polymerization

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Author :
Publisher : Springer
ISBN 13 : 4431541861
Total Pages : 1075 pages
Book Rating : 4.4/5 (315 download)

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Book Synopsis Anionic Polymerization by : Nikos Hadjichristidis

Download or read book Anionic Polymerization written by Nikos Hadjichristidis and published by Springer. This book was released on 2015-09-01 with total page 1075 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents these important facts: a) The mechanism of anionic polymerization, a more than 50-year challenge in polymer chemistry, has now become better understood; b) Precise synthesis of many polymers with novel architectures (triblock, multi-block, graft, exact graft, comb, cyclic, many armed stars with multi-components, dendrimer-like hyper-branched, and their structural mixed (co)polymers, etc.) have been advanced significantly; c) Based on such polymers, new morphological and self-organizing nano-objects and supra molecular assemblies have been created and widely studied and are considered nanodevices in the fields of nano science and technology; d) New high-tech and industrial applications for polymeric materials synthesized by anionic polymerization have been proposed. These remarkable developments have taken place in the last 15 years. Anionic polymerization continues to be the only truly living polymerization system (100 % termination free under appropriate conditions) and consequently the only one with unique capabilities in the synthesis of well-defined (i.e., precisely controlled molecular weight, nearly mono-disperse molecular weight distribution, structural and compositional homogeneity) complex macromolecular architectures. This book, with contributions from the world’s leading specialists, will be useful for all researchers, including students, working in universities, in research organizations, and in industry.

Synthesis of Polyhedral Oligomeric Silsesquioxane(poss)-based Shape Amphiphiles with Two Polymeric Tails of Symmetric Or Asymmetric Compositions

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Publisher :
ISBN 13 :
Total Pages : 41 pages
Book Rating : 4.:/5 (913 download)

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Book Synopsis Synthesis of Polyhedral Oligomeric Silsesquioxane(poss)-based Shape Amphiphiles with Two Polymeric Tails of Symmetric Or Asymmetric Compositions by : Zhao Wang

Download or read book Synthesis of Polyhedral Oligomeric Silsesquioxane(poss)-based Shape Amphiphiles with Two Polymeric Tails of Symmetric Or Asymmetric Compositions written by Zhao Wang and published by . This book was released on 2013 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation in the design and synthesis of a new class of well-defined functionalized polyhedral oligomeric silsesquioxane (POSS)-based shape amphiphiles with two polymeric tails of symmetric or asymmetric compositions raised intensive attention recently. Polyhedral oligomeric silsesquioxanes (POSS), regarded arguably as the smallest silicon nanoparticles with cage diameter around 1.0 nm, are promising nanoscopic building blocks for the development of functional materials with hierarchical structures due to their conformational rigidity, shape persistence and diverse peripheral functionalities. The sequential "grafting-from" approach and thiol-ene "click" surface functionalization were employed in the synthesis, which involved thiol-ene mono-functionalization of octavinylPOSS, ring-opening polymerization, atom transfer radical polymerization for "grafting" polymer tails from the POSS-based macro-initiators with controlled molecular weight and low polydispersity, and subsequent thiol-ene "click" surface functionalization. Surprisingly, the vinyl groups on POSS cages were compatible with atom transfer radical polymerization (ATRP) conditions. Thiol-ene "click" chemistry then was applied to give versatile surface functionalizations onto POSS cage. In this way, the polymer chain composition as well as POSS surface chemistry can be tuned separately and efficiently. All the products have been thoroughly characterized by 1H NMR, 13C NMR, FT-IR, size exclusion chromatography and MALDI-TOF mass spectrometry to establish their chemical structures and purities. These POSS-based shape amphiphiles with novel architecture could serve as important model systems in the study of their self-assembling behaviors in bulk, solution, and thin-film states.

Directed Self-assembly of Block Co-polymers for Nano-manufacturing

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Publisher : Woodhead Publishing
ISBN 13 : 0081002610
Total Pages : 328 pages
Book Rating : 4.0/5 (81 download)

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Book Synopsis Directed Self-assembly of Block Co-polymers for Nano-manufacturing by : Roel Gronheid

Download or read book Directed Self-assembly of Block Co-polymers for Nano-manufacturing written by Roel Gronheid and published by Woodhead Publishing. This book was released on 2015-07-17 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The directed self-assembly (DSA) method of patterning for microelectronics uses polymer phase-separation to generate features of less than 20nm, with the positions of self-assembling materials externally guided into the desired pattern. Directed self-assembly of Block Co-polymers for Nano-manufacturing reviews the design, production, applications and future developments needed to facilitate the widescale adoption of this promising technology. Beginning with a solid overview of the physics and chemistry of block copolymer (BCP) materials, Part 1 covers the synthesis of new materials and new processing methods for DSA. Part 2 then goes on to outline the key modelling and characterization principles of DSA, reviewing templates and patterning using topographical and chemically modified surfaces, line edge roughness and dimensional control, x-ray scattering for characterization, and nanoscale driven assembly. Finally, Part 3 discusses application areas and related issues for DSA in nano-manufacturing, including for basic logic circuit design, the inverse DSA problem, design decomposition and the modelling and analysis of large scale, template self-assembly manufacturing techniques. Authoritative outlining of theoretical principles and modeling techniques to give a thorough introdution to the topic Discusses a broad range of practical applications for directed self-assembly in nano-manufacturing Highlights the importance of this technology to both the present and future of nano-manufacturing by exploring its potential use in a range of fields