Download or read book Self assembly Behavior of Star and Rod coil Block Copolymers in Selective Solvents written by 周勢濠 and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study on Self assembly Behaviors of Conjugated Rod coil Block Copolymers in Selective Solvents Based on Dissipative Particle Dynamics written by 洪瑞祥 and published by . This book was released on 2010 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self Assembly of Rod Coil Block Copolymers written by S. Jenekhe and published by . This book was released on 1999 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymer architectures containing both rigid-rod and flexible-coil blocks have novel self-organizing features and functional properties not possible with coil-coil architectures, We describe the self-assembly of new rod-coil diblock, rod- coil-rod triblock, and coil-rod-coil triblock copolymers from solution and the resulting discrete and periodic mesostmctares with sizes in the 100 nanometer to 200 micrometer range. For example, hollow microspheres, cylindrical microtubules, disc- like lamellae, and doughnut shaped discrete objects self-organized from polyquinoline-b-polystyrene diblocks in a selective solvent for the polyquinolineLA. However, the same rod-coil diblock copolymers in a selective solvent for the polystyrene form hollow spheres which self-order into periodic mesoporous materials B.
Download or read book Amphiphilic Block Copolymers written by P. Alexandridis and published by Elsevier. This book was released on 2000-10-18 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is the belief of the editors of this book that the recognition of block copolymers as being amphiphilic molecules and sharing common features with other well-studied amphiphiles will prove beneficial to both the surfactant and the polymer communities. An aim of this book is to bridge the two communities and cross-fertilise the different fields. To this end, leading researchers in the field of amphiphilic block copolymer self-assembly, some having a background in surfactant chemistry, and others with polymer physics roots, have agreed to join forces and contribute to this book.The book consists of four entities. The first part discusses theoretical considerations behind the block copolymer self-assembly in solution and in the melt. The second part provides case studies of self-assembly in different classes of block copolymers (e.g., polyethers, polyelectrolytes) and in different environments (e.g., in water, in non-aqueous solvents, or in the absence of solvents). The third part presents experimental tools, ranging from static (e.g., small angle neutron scattering) to dynamic (e.g., rheology), which can prove valuable in the characterization of block copolymer self-assemblies. The fourth part offers a sampling of current applications of block copolymers in, e.g., formulations, pharmaceutics, and separations, applications which are based on the unique self-assembly properties of block copolymers.
Download or read book Self Assembly of Ordered Microporous Materials from Rod Coil Block Copolymers written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rod-coil diblock copolymers in a selective solvent for the coillike polymer self-organize into hollow spherical micelles having diameters of a few micrometers. Long-range, close-packed, self-ordering of the micelles produced highly iridescent periodic microporous materials. Solution cast micellar films consisted of multilayers of hexagonally ordered arrays of spherical holes whose diameter, periodicity, and wall thickness depended on copolymer molecular weight and composition. Addition of fullerenes into the copolymer solutions also regulated the microstructure and optical properties of the microporous films. These results demonstrate the potential of hierarchical self-assembly of macromolecular components for engineering complex two- and three-dimensional periodic and functional mesostructures.
Download or read book Block Copolymers I written by Volker Abetz and published by Springer Science & Business Media. This book was released on 2005-12-02 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1 N. Hadjichristidis, M. Pitsikalis, H. Iatrou: Synthesis of Block Copolymers.- 2 V. Abetz: Phase Behaviour and Morphologies of Block Copolymers.-
Download or read book Self assembly of Block Copolymers in Dilute Solution written by Kathleen A. Cogan and published by . This book was released on 1991 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self assembly of Rod coil Block Copolymers written by Nicolas Sary and published by . This book was released on 2009 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Controlled Self assembly of Conjugated Rod coil Block Copolymers for Applications in Organic Optoelectronics written by Yuefei Tao and published by . This book was released on 2008 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Self assembly and Structure property Relationships in Block Copolymers written by Manas Ravindra Shah and published by . This book was released on 2009 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers have been subject of tremendous research interest owing to their capability of undergoing self-assembly which allows them to tailor their electrical, optical, and mechanical properties. Statistical mechanics of flexible block copolymers is well understood. However, there are many unresolved issues with confinement of block copolymers as well as structure formation in block copolymers having non-flexible polymer blocks. We develop mean field theory models to address the issues arising in thermodynamics of such complex block copolymers. Also, we develop theoretical formalisms to understand the link between morphology and macroscopic properties in these block copolymers. We study the stability and ordering in thin films of flexible diblock copolymer in the presence of compressible solvent using a combined polymer mean field theory and lattice gas model for binary fluid mixtures. We utilize mean field theory model to understand the self-assembly behavior in side-chain liquid crystalline block copolymers which involve interplay between microphase separation and liquid crystalline ordering of side chain mesogenic units. We extend the field theoretic models for block copolymer to account for self-assembly in semicrystalline block copolymers. The semicrystalline chain is modeled as a semiflexible chain having non-bonded attractions between parallel bonds. We characterize the structure formation in such block copolymers as a function of the rigidity of the semicrystalline chain. Then we extend the formalism to study semicrystalline triblock and pentablock copolymers and evaluate bridging fractions in different sequences of semicrystalline multiblock copolymers. Rod-coil block copolymers have a flexible polymer covalently linked to rigid polymer. Such polymers have potential applications as organic LEDs and photovoltaic devices. We study the self-assembly of such block copolymer under confinement. To make these block copolymers viable as photovoltaic devices, we performed the photovoltaic modeling of devices based on self-assembly of block copolymers. We characterize the interplay between self-assembly and anisotropy of charge transport (arising due to rigid polymer chains) in determining the eventual photovoltaic properties.
Download or read book Solvent Vapor Assisted Self Assembly of Patternable Block Copolymers written by Joan K. Bosworth and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymer self assembly presents a method for patterning and templating applications on the 10-50 nm length scale, a smaller scale than can be easily achieved by photolithography. Here we investigate the use of functionalized polar-nonpolar block copolymers both as photopatternable self-assembling materials and for selective infiltration of one block for patterning. Block copolymer thin films with defect-free self-assembled morphology over large domains combined with careful control of the orientation of the morphology are critical for these patterning applications. Self assembly of block copolymers is facilitated by polymer chain mobility, commonly achieved by heating block copolymer films above the glass transition temperature of the blocks. However, many block copolymer systems, including those discussed here, are thermally incompatible. Swelling in a solvent vapor, called solvent annealing, provides sufficient mobility for self assembly. Solvent annealing proved critical to forming ordered structures of functional polar-nonpolar block copolymer thin films. Thermal instability initially led to limited self assembly of combined topdown/bottom-up block copolymer systems. In this case, photolithographic functionality has been designed into block copolymers, allowing the majority component of a block copolymer to behave as a negative-tone photoresist. Solvent vapor annealing has provided a simple and inexpensive method for allowing the bottom-up self assembly of these top-down photopatternable materials. An additional benefit of solvent annealing is the ability to reversibly tune the morphology formed using the selectivity of different swelling solvents to the two blocks: that is, the choice of solvent for annealing directs the formation of different morphologies in the dried film, here spherical and cylindrical. This behavior is reversible, alternating annealing sessions lead to switching of the morphology in the film. Secondary ordering techniques applied in tandem with solvent annealing can be used to further control the self assembly and give highly ordered block copolymer domains. Here we demonstrate the use of graphoepitaxy to align block copolymer self assembly to patterns in substrates. The combination of block copolymer self assembly with lithographic crosslinking in films was initially pursued to allow precise location of assembled patterns. Taking this behavior a step further, we combine solvent annealing, used to reversibly tune the self-assembled morphology, and lithographic patterning, used to prevent switching in exposed regions. This combined process has provided a method for selectively patterning 100 nm-wide domains of spherical morphology within regions of parallel-oriented cylindrical morphology. We also investigate solvent annealing of a block copolymer blended with a hydrogen bonding material that selectively segregates into the polar block. Blending provides a method of tuning the periodicity upon solvent annealing for self assembly, with morphology control again possible by solvent selectivity. Selective extraction of the blended material forms voids displaying the tunable periodicity, and the pattern is then transferred by templating to inorganic materials.
Download or read book Self assembly of Rod coil Block Copolymers written by Rachel A. Segalman and published by . This book was released on 2008 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self assembly of Rod coil Block Copolymers from Weakly to Moderately Segregated Regimes written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure and Thermodynamics of Rod coil Block Copolymers written by Bradley David Olsen and published by . This book was released on 2007 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self assembly Behavior in Hydrophilic Block Copolymers written by Clara Valverde Serrano and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers are receiving increasing attention in the literature. Reports on amphiphilic block copolymers have now established the basis of their self-assembly behavior: aggregate sizes, morphologies and stability can be explained from the absolute and relative block lengths, the nature of the blocks, the architecture and also solvent selectiveness. In water, self-assembly of amphiphilic block copolymers is assumed to be driven by the hydrophobic. The motivation of this thesis is to study the influence on the self-assembly in water of A b B type block copolymers (with A hydrophilic) of the variation of the hydrophilicity of B from non-soluble (hydrophobic) to totally soluble (hydrophilic). Glucose-modified polybutadiene-block-poly(N-isopropylacrylamide) copolymers were prepared and their self-assembly behavior in water studied. The copolymers formed vesicles with an asymmetric membrane with a glycosylated exterior and poly(N-isopropylacrylamide) on the inside. Above the low critical solution temperature (LCST) of poly(N-isopropylacrylamide), the structure collapsed into micelles with a hydrophobic PNIPAM core and glycosylated exterior. This collapse was found to be reversible. As a result, the structures showed a temperature-dependent interaction with L-lectin proteins and were shown to be able to encapsulate organic molecules. Several families of double hydrophilic block copolymers (DHBC) were prepared. The blocks of these copolymers were biopolymers or polymer chimeras used in aqueous two-phase partition systems. Copolymers based on dextran and poly(ethylene glycol) blocks were able to form aggregates in water. Dex6500-b-PEG5500 copolymer spontaneously formed vesicles with PEG as the "less hydrophilic" barrier and dextran as the solubilizing block. The aggregates were found to be insensitive to the polymer's architecture and concentration (in the dilute range) and only mildly sensitive to temperature. Variation of the block length, yielded different morphologies. A longer PEG chain seemed to promote more curved aggregates following the inverse trend usually observed in amphiphilic block copolymers. A shorter dextran promoted vesicular structures as usually observed for the amphiphilic counterparts. The linking function was shown to have an influence of the morphology but not on the self-assembly capability in itself. The vesicles formed by dex6500-b-PEG5500 showed slow kinetics of clustering in the presence of Con A lectin. In addition both dex6500-b-PEG5500 and its crosslinked derivative were able to encapsulate fluorescent dyes. Two additional dextran-based copolymers were synthesized, dextran-b-poly(vinyl alcohol) and dextran-b-poly(vinyl pyrrolidone). The study of their self-assembly allowed to conclude that aqueous two-phase systems (ATPS) is a valid source of inspiration to conceive DHBCs capable of self-assembling. In the second part the principle was extended to polypeptide systems with the synthesis of a poly(N-hydroxyethylglutamine)-block-poly(ethylene glycol) copolymer. The copolymer that had been previously reported to have emulsifying properties was able to form vesicles by direct dissolution of the solid in water. Last, a series of thermoresponsive copolymers were prepared, dextran-b-PNIPAMm. These polymers formed aggregates below the LCST. Their structure could not be unambiguously elucidated but seemed to correspond to vesicles. Above the LCST, the collapse of the PNIPAM chains induced the formation of stable objects of several hundreds of nanometers in radius that evolved with increasing temperature. The cooling of these solution below LCST restored the initial aggregates. This self-assembly of DHBC outside any stimuli of pH, ionic strength, or temperature has only rarely been described in the literature. This work constituted the first formal attempt to frame the phenomenon. Two reasons were accounted for the self-assembly of such systems: incompatibility of the polymer pairs forming the two blocks (enthalpic) and a considerable solubility difference (enthalpic and entropic). The entropic contribution to the positive Gibbs free energy of mixing is believed to arise from the same loss of conformational entropy that is responsible for "the hydrophobic effect" but driven by a competition for water of the two blocks. In that sense this phenomenon should be described as the "hydrophilic effect".
Download or read book Rod rod and Rod coil Self assembly and Phase Behavior of Polypeptide Diblock Copolymers written by Elizabeth A. Minich and published by . This book was released on 2003 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Facile Approach for Rapid and Tunable Self assembly of Rod coil Block Copolymers written by 吳尚融 and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
