Papers by Keyword: Block-Copolymer

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Authors: Hiroki Uehara, Masaki Kakiage, Hidekazu Tanaka, Takeshi Yamanobe
Abstract: Structural deformation during uniaxial drawing of polyethylene-block-polystyrene (PE-b-PS) copolymer film was analyzed by in-situ small angle X-ray scattering (SAXS) measurement. The PE-b-PS film was prepared by solution casting, followed by isothermally crystallizing from melt. The obtained film exhibits the characteristic bicontinuous crystalline/amorphous morphology. Initial stage of uniaxial drawing induces the orientation of such crystalline/amorphous phases, but these phase separation is destroyed in the latter stage. In contrast, solvent swelling treatment successfully induces the orientation of crystalline/amorphous phases with keeping the phase continuity.
Authors: Yun Suk Jo, Do-Kyung Kim, Young Keun Jeong, Kyung Ja Kim, Mamoun Muhammed
Abstract: A novel approach to load a hydrophilic bovine serum albumin (BSA) into the drug carriers was proposed in terms of thermosensitive dual-shell structures which were fabricated with poly(N-isopropylacrylamide), poly(lactide) and Au nanoparticles. Spherically well-defined dualshell structures were constructed by a modified-double-emulsion method (MDEM). The lower critical solubility temperature of the structures was shifted to 36.4 °C which was confirmed by UVVis spectroscopy.
Authors: You Qing Jiang, Yun Bo Zhang, Zhi Yong Lin, Jun Chen, Ming Ming Yu
Abstract: Block copolymer consists of two and more than two of different polymer links. Epoxy terminated polydtyrene (Ps-ep) active polymer was used to polymerize polystyrene (Pst)-polyethylene oxide (Peo) block copolymer P (st-b-eo). There were the mixtures of (Ps-ep), (Pst), (Peo) and P (st-b-eo) in the polymerization. It is necessary to separate (Ps-ep), (Pst), (Peo) and P (st-b-eo) in the mixtures in order to determine structure parameters of P (st-b-eo) block copolymers. We can know for certain their types of ABA, BAB and AB of polystyrene (A)-Polyethylene oxides (B) block copolymers with analysis of gel permeation chromatography (GPC).
Authors: S.A. Shamsudin, Hirokazu Hasegawa, Mikihito Takenaka, Saijo Kenji
Abstract: Quantum dots (QDs) have a great potential to be applied as a biosensor to detect cancer cells because of their properties such as high photoluminescence, photo stability, narrow peak of luminescence, etc. However, cadmium sulphide (CdS) quantum dots are toxic and hydrophobic, making it impossible to be applied into biomaterials. A template is needed to make CdS QDs nontoxic and hydrophilic. The optical properties of these QDs are needed to be protected. To achieve this purpose, the template for CdS QDs has been designed by capping CdS QDs with apo-ferritin shells before aligning them onto cylindrical perpendicular PS-b-P2VP template, with the aim of locating CdS QDs appropriately in sequence. A host-guest system can be developed.
Authors: Xin Kang Gao, Jun Liu, Ting Hua Wang, Xue Li, Xiao Kai Zhang
Abstract: In this study, a method to generate arrays of Fe3O4 nanoparticles (MNPs) via block copolymer (BC) self-assembly was developed. A composite film of polystyrene-block-poly (2-vinylpyridine) (PS-b-P2VP)/MNPs was first prepared by spin-coating the PS-b-P2VP/MNPs mixed solution on a carbon substrate. After the composite film was annealed at high temperature for 2 days, it was found that the modified MNPs could be selectively incorporated into P2VP cylinders in PS-b-P2VP diblock copolymers and the P2VP cylinders were oriented parallel to the substrate. For a long time annealing (10 days), the P2VP cylinders become normal to the substrate and MNPs are located at the interface of P2VP and PS phases.
Authors: Chang Hao Yan, Zhi Jiao Zhang, Hai Yan Chen, Zhong Yi Xie, Ting Zhu, Ming Zhang
Abstract: The polystyrene with end group of Br was synthesized by using MBrP as the initiator, CuBr/ PMDETA as the catalyst system according to atom transfer radical polymerization (ATRP). The effect of reaction temperature was studied and the system was confirmed as the active polymerization. Then PS-Br and CuBr/ PMDETA were respectively used as macroinitiator and catalyst to polymerize tBMA according to atom transfer radical polymerization (ATRP). The structure of the product was characterized by GPCFTIR1H-NMR. The amphiphilic block copolymer was obtained after hydrolysis. And the honeycomb porous film was prepared by PS-b-PMAA through using breath figure method.
Authors: Yong Zhi Cao, Shen Dong, Ying Chun Liang, Tao Sun, Yong Da Yan
Abstract: Ultrathin block copolymer films are promising candidates for bottom-up nanotemplates in hybrid organic-inorganic electronic, optical, and magnetic devices. Key to many future applications is the long range ordering and precise placement of the phase-separated nanoscale domains. In this paper, a combined top-down/bottom-up hierarchical approach is presented on how to fabricate massive arrays of aligned nanoscale domains by means of the self-assembly of asymmetric poly (styrene-block-ethylene/butylenes-block-styrene) (SEBS) tirblock copolymers in confinement. The periodic arrays of the poly domains were orientated via the introduction of AFM micromachining technique as a tool for locally controlling the self-assembly process of triblock copolymers by the topography of the silicon nitride substrate. Using the controlled movement of 2- dimensional precision stage and the micro pressure force between the tip and the surface by computer control system, an artificial topographic pattern on the substrate can be fabricated precisely. Coupled with solvent annealing technique to direct the assembly of block copolymer, this method provides new routes for fabricating ordered nanostructure. This graphoepitaxial methodology can be exploited in hybrid hard/soft condensed matter systems for a variety of applications. Moreover, Pairing top-down and bottom-up techniques is a promising, and perhaps necessary, bridge between the parallel self-assembly of molecules and the structural control of current technology.
Authors: Jaeup U. Kim
Abstract: Patterned substrates are good candidates to enhance the arrangement of nanodomains in block copolymer thin films. Here, I theoretically demonstrate the possibility to self-assemble block copolymers on top of physically or chemically patterned substrates. The presence of substrate pattern not only enhances the alignment of polymers, but also induces novel new morphologies which were not present in the bulk phase diagram.
Authors: Hai Dan Lin, Xiao Ying Yang, Cheng Xun Sun
Abstract: A new series of hydrophobic-hydrophilic multiblock sulfonated poly (arylene ether ketone)-b-poly (arylene ether ketone) copolymers were successfully synthesized and evaluated for use as proton exchange membranes (PEMs). The membrane properties of block copolymers including ion exchange capacities (IECs), water uptake and proton conductivities were characterized for the multiblock copolymers and compared with random sulfonated poly (arylene ether) s and other multiblock copolymer membranes at similar ion exchange capacity value. This series of multiblock copolymers showed moderate conductivities up to 0.063 S/cm at 80 °C with very low water uptake of 19%. Therefore, they are considered to be promising PEM materials for fuel cells.
Authors: Agnieszka Tercjak, Junkal Gutierrez, Iñaki Mondragon
Abstract: The main aim of this work was the generation of novel smart materials, in this case thermo-responsive inorganic/organic meso/nanostructured hybrids based on different low molecular weight liquid crystals (LC) and conductive rutile TiO2 nanoparticles. LC as partially miscible with polystyrene (PS) was well-dispersed using amphiphilic poly (styrene-b-ethylene oxide) block copolymers (PS-b-PEO). Simultaneously, LC was used as surfactant for conductive rutile TiO2 nanoparticles.
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