Preparation of Nanoporous Poly(Methyl Silsesquioxanes) Films Using PS-b-P4VP as Template

2008 ◽  
Vol 8 (3) ◽  
pp. 1537-1544 ◽  
Author(s):  
Yang-Yen Yu ◽  
Chang-Chung Yang
Keyword(s):  
Hydrogen Bonding ◽  
The Other ◽  
Theoretical Studies ◽  
Intermolecular Hydrogen Bonding ◽  
Pore Morphology ◽  
Nanoporous Films ◽  
Vinyl Pyridine ◽  
Loading Ratio ◽  
Copolymer Poly ◽  
Experimental And Theoretical Studies

Nanoporous poly(methyl silsesquioxane) (PMSSQ) film was prepared through the templating of an amphiphilic block copolymer, poly(styrene-4-vinyl pyridine) (PS-b-P4VP). The experimental and theoretical studies suggest that the intermolecular hydrogen bonding is existed between the PMSSQ precursor and PS-b-P4VP. The miscible hybrid and the narrow thermal decomposition of the PS-b-P4VP lead to nanopores in the prepared films from the results of TGA, AFM, and TEM. The effects of the loading ratio on the morphology and properties of the prepared nanoporous PMSSQ films were investigated. The TEM and AFM studies show that the uniform pore morphology with pore size 10–15 nm can be prepared from a modest porogen loading level for the optimum intermolecular hydrogen bonding. The refractive index and dielectric constant of the prepared nanoporous films decreases with an increase in PS-b-P4VP loading. On the other hand, the porosity increases with an increasing PS-b-P4VP loading. This study demonstrates a methodology to control pore morphology and properties of the nanoporous PMSSQ films through the templating of PS-b-P4VP.

Preparation of Nanoporous Mondispersed Silica Nanoparticles Films Using Poly(styrene)- Block-Poly( 2-Vinyl Pyridine) as Template

2008 ◽  
Vol 47-50 ◽  
pp. 646-649
Author(s):  
Yang Yen Yu ◽  
Wen Chen Chien ◽  
Shih Ting Chen
Keyword(s):  
Hydrogen Bonding ◽  
Silica Nanoparticles ◽  
Colloidal Silica ◽  
Nanoporous Silica ◽  
Intermolecular Hydrogen Bonding ◽  
Pore Morphology ◽  
Silica Films ◽  
Nanoporous Films ◽  
Vinyl Pyridine ◽  
Copolymer Poly

Nanoporous silica films were prepared through the templating of amphiphilic block copolymer, poly(styrene-2-vinyl pyridine) (PS-b-P2VP), and colloidal silica nanoparticles. The experimental and theoretical studies suggested that the intermolecular hydrogen bonding was existed between the colloidal silica nanoparticles and PS-b-P2VP. The miscible hybrid and the narrow thermal decomposition of the PS-b-P2VP led to nanopores in the prepared films from the results of TGA, AFM, and TEM. The effects of the loading ratio and P2VP chain length on the morphology and properties of the prepared nanoporous silica films were investigated. The TEM and AFM studies showed that the uniform pore morphology with pore size 10-15nm was prepared from a modest porogen loading level for the optimum intermolecular hydrogen bonding. The refractive index and dielectric constant of the prepared nanoporous films decreased with an increase in PS-b-P2VP loading. On the other hand, the porosity increased with an increasing PS-b-P2VP loading. This study demonstrated a methodology to control pore morphology and properties of the nanoporous silica films through the templating of PS-b-P2VP.

scholarly journals Flexible Epoxy Resins Formed by Blending with the Diblock Copolymer PEO-b-PCL and Using a Hydrogen-Bonding Benzoxazine as the Curing Agent

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 201 ◽  
Author(s):  
Wei-Chen Su ◽  
Fang-Chang Tsai ◽  
Chih-Feng Huang ◽  
Lizong Dai ◽  
Shiao-Wei Kuo
Keyword(s):  
Hydrogen Bonding ◽  
Diblock Copolymer ◽  
Mechanical Analysis ◽  
Intermolecular Hydrogen Bonding ◽  
Curing Agent ◽  
Thermal Curing ◽  
Scanning Calorimetry ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Copolymer Poly

In this study, we enhanced the toughness of epoxy resin by blending it with the diblock copolymer poly(ethylene oxide–b–ε-caprolactone) (PEO-b-PCL) with a benzoxazine monomer (PA-OH) as the thermal curing agent. After thermal curing, Fourier transform infrared spectroscopy revealed that intermolecular hydrogen bonding existed between the OH units of the epoxy–benzoxazine copolymer and the C–O–C (C=O) units of the PEO (PCL) segment. Differential scanning calorimetry and dynamic mechanical analysis revealed that the glass transition temperature and storage modulus of the epoxy–benzoxazine matrix decreased significantly upon increasing the concentration of PEO-b-PCL. The Kwei equation predicted a positive value of q, consistent with intermolecular hydrogen bonding in this epoxy–benzoxazine/PEO-b-PCL blend system. Scanning electron microscopy revealed a wormlike structure with a high aspect ratio for PEO-b-PCL as the dispersed phase in the epoxy–benzoxazine matrix; this structure was responsible for the improved toughness.

Isostructuralism among `bridge-flipped' isomeric benzylideneanilines and phenylhydrazones

2007 ◽  
Vol 63 (3) ◽  
pp. 485-496 ◽  
Author(s):  
William H. Ojala ◽  
Jonathan M. Smieja ◽  
Jill M. Spude ◽  
Trina M. Arola ◽  
Marika K. Kuspa ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
The Other ◽  
Intermolecular Hydrogen Bonding ◽  
Solid Materials ◽  
Cell Dimensions ◽  
Molecular And Crystal Structures ◽  
Packing Arrangement ◽  
The Individual ◽  
Unit Cell Dimensions ◽  
Similar Unit

`Bridge-flipped' isomers may be defined as pairs of molecules related by a reversal of a bridge of atoms connecting two major parts of the individual molecules. This kind of isomerism is commonly found among benzylideneanilines and phenylhydrazones. Isostructural pairs might be suitable for co-crystallization and are thus useful in the preparation of new solid materials. Although most of the examples of bridge-flipped isomeric benzylideneanilines and phenylhydrazones in the crystallographic literature are not isostructural, a small number of isostructural pairs have been reported by previous workers. This paper describes the molecular and crystal structures of four pairs of bridge-flipped isomers: two isostructural phenylhydrazones, (E)-2-bromobenzaldehyde 4-cyanophenylhydrazone (I) and (E)-4-cyanobenzaldehyde 2-bromophenylhydrazone (II); two pairs of isostructural benzylideneanilines, N-(2-trifluoromethylbenzylidene)-2-methylaniline (III) and N-(2-methylbenzylidene)-2-trifluoromethylaniline (IV), and N-(2-bromobenzylidene)-2-methylaniline (V) and N-(2-methylbenzylidene)-2-bromoaniline (VI); and a pair of benzylideneanilines with closely similar unit-cell dimensions but different packing arrangements, N-(4-methylbenzylidene)-4-cyanoaniline (VII) and N-(4-cyanobenzylidene)-4-methylaniline (VIII). The structure of (V) is disordered. The packing arrangement of (VIII) resembles that of the chloro-/methyl-substituted benzylideneanilines MBZCLA/MBZCLB [N-(4-methylbenzylidene)-4-chloroaniline and N-(4-chlorobenzylidene)-4-methylaniline]. Although intermolecular hydrogen bonding plays a part in the isostructuralism of the two phenylhydrazones, the other examples of isostructuralism occur in the absence of similar, relatively strong intermolecular interactions.

Protein structural transitions and their functional role

2004 ◽  
Vol 363 (1827) ◽  
pp. 331-356 ◽  
Author(s):  
Martin Karplus ◽  
Yi Qin Gao ◽  
Jianpeng Ma ◽  
Arjan van der Vaart ◽  
Wei Yang
Keyword(s):  
Escherichia Coli ◽  
Protein Folding ◽  
Functional Role ◽  
Motor Protein ◽  
Molecular Machines ◽  
Living Cells ◽  
The Other ◽  
Theoretical Studies ◽  
Structural Transitions ◽  
Experimental And Theoretical Studies

Living cells are a collection of molecular machines which carry out many of the functions essential for the cell's existence, differentiation and reproduction. Most, though not all, of these machines are made up of proteins. Because of their complexity, an understanding of how they work requires a synergistic combination of experimental and theoretical studies. In this paper we outline our studies of two such protein machines. One is GroEL, the chaperone from Escherichia coli , which aids in protein folding; the other is F 1 –ATPase, a motor protein which synthesizes and hydrolyses ATP.

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