Structure and property optimization of perfluorinated short side chain membranes for hydrogen fuel cells using orientational stretching

RSC Advances ◽  
2016 ◽  
Vol 6 (110) ◽  
pp. 108864-108875 ◽  
Author(s):  
Yu. V. Kulvelis ◽  
S. S. Ivanchev ◽  
O. N. Primachenko ◽  
V. T. Lebedev ◽  
E. A. Marinenko ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Neutron Scattering ◽  
Scattering Data ◽  
Side Chain ◽  
Low Molecular Weight ◽  
Hydrogen Fuel Cells ◽  
Hydrogen Fuel ◽  
Short Side ◽  
Structure And Property ◽  
Structure Rearrangement

Stretching of membranes with low molecular weight makes structure rearrangement according to neutron scattering data on D2O-filled membranes.

Sodium-Catalyzed Copolymerization of 1,3-Butadiene and Styrene

1947 ◽  
Vol 20 (1) ◽  
pp. 1-13
Author(s):  
C. S. Marvel ◽  
W. J. Bailey ◽  
G. E. Inskeep
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Side Chain ◽  
Low Molecular Weight ◽  
Monomer Mixture ◽  
Laboratory Procedure ◽  
Styrene Content ◽  
Polymerization Method

Abstract 1. A convenient laboratory procedure for the sodium-catalyzed copolymerization of butadiene and styrene has been described. Earlier attempts to accomplish this probably failed because the monomers were not sufficiently pure. 2. The copolymer of butadiene and styrene which results from sodium polymerization is different from the emulsion copolymer, GR-S, in several important respects. The sodium-catalyzed copolymer has a more nearly constant styrene content at different stages of conversion; it is made up of molecules with a relatively narrow molecular weight spread; it has a higher intrinsic viscosity; it is 100 per cent soluble in benzene (i.e., there is no gel) even at 100 per cent conversion; when treated with standard rubber antioxidant, it ages better; and it has a greater amount of the butadiene joined in the 1,2 manner (i.e., greater vinyl side-chain content). 3. The effects of such variables as temperature of polymerization, method of adding the monomer mixture to the catalyst, size of catalyst particles, and possible butadiene impurities on the polymerization have been studied. 4. The method has been extended to cover copolymerization of butadiene and m-methylstyrene to give a soluble copolymer of low molecular weight. Other styrene-type monomers gave less interesting copolymers.

Flory's parameters in solutions of liquid-crystalline side-chain polymers in low-molecular weight liquid crystals

1990 ◽  
Vol 23 (23) ◽  
pp. 5020-5024 ◽  
Author(s):  
Gilles Sigaud ◽  
M. F. Achard ◽  
F. Hardouin ◽  
C. Coulon ◽  
H. Richard ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Side Chain ◽  
Low Molecular Weight

Phenylalanine and derivatives as versatile low-molecular-weight gelators: design, structure and tailored function

2018 ◽  
Vol 6 (1) ◽  
pp. 38-59 ◽  
Author(s):  
Tanmay Das ◽  
Marleen Häring ◽  
Debasish Haldar ◽  
David Díaz Díaz
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Essential Amino Acid ◽  
Side Chain ◽  
Low Molecular Weight ◽  
Design Structure ◽  
Hydrophobic Nature ◽  
Low Molecular Weight Gelators

Phenylalanine (Phe) is an essential amino acid classified as neutral and nonpolar due to the hydrophobic nature of the benzyl side chain.

Aggregation Structure and Electro—Optical Properties of (Liquid Crystalline Polymer)/(Low Molecular Weight Liquid Crystal) Composite System

1989 ◽  
Vol 171 ◽  
Author(s):  
Tisato Kajiyama ◽  
Hirotsugu Kikuchi ◽  
Akira Miyamoto ◽  
Satoru Moritomi ◽  
Jenn—Chiu Hwang
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Electric Field ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Smectic Phase ◽  
Side Chain ◽  
Low Molecular Weight ◽  
Smectic Layer

ABSTRACTA series of thin films composed of liquid crystalline polymer (LCP) and low molecular weight liquid crystal (LMWLC) was prepared by a solventcasting method or by a bar—coating method. LCPs were of mesogenic side chain type with strong or weak polar terminalgroups in the side chain portion. A mixture of smectic LCP (LCP with side chain of strong polar end) and nematic LMWLC formed a smectic phase in a LCP weight fraction range above 50 %. Also, a mixture of nematic LCP (LCP with side chain of weak polar end) and nematic LMWLC with strong polar group induced a new smectic phase in a LCP molar fraction range of 20–80 %. Reversible and bistable electro-optical effects based on light scattering were recognized for a smectic phase of a binary composite composed of LCP and LMWLC. A light scattering state caused by many fragmented smectic lamellae appeared in the case of application of an a.c. electric field below a threshold frequency (∼l Hz). Furthermore, application of a 100 Vp—p a.c. field of 1 kHz made the transmission light intensity increased to 94 % within a few seconds. The optical heterogeneity in asmectic layer composed of the side chain group of LCP was caused by the difference of twoforces based on both dielectric anisotropy of the side chain and electrohydrodynamic motion of the main chain. Since application of a low frequency electric field causes an ioniccurrent throughout the mixture film, it is reasonable to consider that an induced turbulent flow of main chains by an ionic current collapsed a fairly well organized large smectic layer into many small fragments, resulting in an increase in light scattering. The response speed of LCP upon application of an electric field increased remarkably by mixingLMWLC. In the case of a smectic mesophase, turbid and transparent states remained unchanged as it was, even though after removing an electric field.1Such abistable and reversiblelight switching driven by two different frequencies of electric field could be newly realized by both characteristics of turbulent effect of a wellorganized large smectic layer of LCP and rapid response of LMWLC. We believe that the LCP/LMWLC mixture system is promissing as a novel type of “light valve” exhibiting memory effect (bistable light switching).

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