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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 349 for “"Block Copolymers"”.
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Ceramic nanostructures for block copolymers
… media) become smaller and smaller. In this work, block copolymers are harnessed in order to produce both porous and relief nanostructures. The interest in using these materials is due to the unique morphologies that block copolymers form and the fact that these nanostructures do so by self …
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Liquid crystalline multi-block copolymers
Lyotropic and thermotropic high strength liquid crystalline polymers have become an important area of research and development in polymeric, high performance materials. These materials have afforded excellent high temperature stability and high strength in the oriented direction, but not in the …
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Bottlebrush block copolymers for photonic materials
Block copolymer self-assembly has proven to be an effective route for the fabrication of photonic films and, more recently, photonic pigments. However, despite extensive research on this topic over the past two decades, the palette of monomers and polymers employed to produce such structurally …
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Photo-responsive liquid crystal block copolymers/
… into photo-actuation, polystyrene (PS) end blocks were added to the poly(vinylmethylsiloxane) (PVMS) to produce PS-b-PVMS-b-PS, which is important in and of itself because the PVMS has a very low Tg and a functionalizable backbone and the PS end blocks make the material a thermoplastic …
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Dynamics of rod-coil block copolymers
… domains of dissimilar geometries. Rod-coil block copolymers are an example of hybrid molecules that have attracted recent interest for organic electronics and biomaterials. This thesis uses theory, simulation, and experiments to better understand the mechanisms of molecular motion in …
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Model adhesive studies using block copolymers
… a series of styrene-isoprene-styrene linear triblock copolymers as model hot-melt adhesives for titanium 6-4 alloy substrates. The block copolymer samples have narrow molecular weight distributions and styrene contents ranging from 20 to 60% by weight. For these systems a finite number of …
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Fundamental adhesive studies of block copolymers
… adhesion technology. Styrene and isoprene based block copolymers were investigated 511 order to understand their adhesive properties. The structure of the microphase separated morphology of the materials studied was found to influence the adhesive behavior in applications as hot melt/structural …
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Engineering properties of multiphase block copolymers
Multiblock [-A-B-]<sub>n</sub> copolymers of bisphenol-A polycarbonate (I) and several poly(arylether sulfones) (II) have been investigated. The copolymers [see document for a diagram of copolymers (I) and (II)] were prepared from hydroxyl terminated oligomers (4,000 < M̅<sub>n</sub> < 30,000) by …
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Self-assembly behavior in hydrophilic block copolymers
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 …
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Synthesis and characterisation of vinyl block copolymers
… weight and molecular weight distributions. Diblock copolymers of styrene-b-methyl methacrylate were synthesised at -78oC in THF in the presence of lithium chloride, and at ambient temperatures in toluene in the presence of aluminium alkyls. Studies in the presence of lithium chloride showed …
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Cell dynamical system approach to block copolymers
In this thesis we discuss a mesoscale model of block-copolymer (BCP) microphase separation dynamics based on a cell dynamics system (CDS) model. The model suggests a partial differential equation (PDE) model that allows us to find a close relation between the block copolymer and spinodal …
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Shear induced morphology of semicrystalline block copolymers
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994.
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Templated self-assembly of novel block copolymers
Self-assembly of block copolymers (BCPs) is emerging as a promising route for numerous technological applications to fabricate a variety of nanoscopic structures. The resulting feature sizes range from a few to several hundred nanometers, and are readily tunable by varying the molecular weights of …
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Polysiloxane-polyarylester block copolymers: synthesis and characterization
… and characterization of multiphase, transparent block copolymers that are potential candidates for passive damping applications in large space structures. Relatively high molecular weight polysiloxane-polyarylester block copolymers were prepared by two different synthetic routes. A solution …
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Gas permeability of polyimide/polysiloxane block copolymers
… poly(dimethylsiloxane) microphase separated block copolymers ranging from 0-50 wgt. % poly(dimethylsiloxane) have been measured for permeability characteristics. The polyimide segment of the copolymers was based on oxydiphthalicdianhydride (ODPA) and 1,4-Bis(4-amino-1,1- …
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Self-Assembly of Block Copolymers in External Fields
… external fields on the microdomain structure of block copolymers has been studied. Both surface fields and electric fields have been considered. External electric fields are used to create macroscopically oriented bulk samples. In order to circumvent limitations associated with the application of …
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Smart Hydrogels based on Responsive Star-Block Copolymers
… the synthesis of double-responsive star-shaped block copolymers and their formation of smart hydrogels in response to different external stimuli, specifically temperature and pH. Our concept was based on (AB)x diblock copolymer stars where both blocks are responsive to temperature and pH. This …
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Twofold switchable block copolymers based on new polyzwitterions
… in specific aqueous environments. Water-soluble block copolymers were prepared from the zwitterionic monomers and the non-ionic monomer N-isopropylmethacrylamide (“NIPMAM”) by the RAFT polymerization. Such block copolymers with two hydrophilic blocks exhibit twofold thermoresponsive behavior in …
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Amphiphilic linear-dendritic block copolymers for drug delivery
… In this thesis, an amphiphilic linear-dendritic block copolymer was designed, synthesized, and applied as a new polymeric drug delivery platform. First, to develop the drug delivery vehicle, an ABA dendritic-linear-dendritic block copolymer consisting of poly(amidoamine) (PAMAM) and …
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Molecular design of ordering transitions in block copolymers
The tendency of block copolymers (BCP's) to microphase separate at the molecular level, producing a wide array of ordered nanostructures, is of particular interest from an engineering standpoint due to the unique mechanical, optical or electrical properties that ensue. Upon considering the …
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