Liquid crystal alignment property of n‐alkylthiomethyl‐ or n‐alkylsulfonylmethyl‐substituted polystyrenes

Abstract

We synthesized a series of n‐alkylthiomethyl‐substituted polystyrenes (#T‐PS, # = 4, 8, 12, and 16) and n‐alkylsulfonylmethyl‐substituted polystyrenes (#S‐PS, # = 4, 8, 12, and 16), where # is the number of carbon atoms in the n‐alkyl side group of the polymers, using polymer analogous reactions to investigate their liquid crystal (LC) alignment properties. In general, the LC cell fabricated using the polymer film having a longer n‐alkyl side group, a thioether linkage group, and a higher molar content of n‐alkyl side group showed homeotropic LC alignment behavior with a pretilt angle of about 90°. The homeotropic alignment behavior was well correlated with the surface energy of the polymer films; when the positive dielectric anisotropic LC (ZLI‐5900‐000 from Merck) and negative dielectric anisotropic LC (MLC‐7026‐000 from Merck) were used to fabricate the LC cells, homeotropic alignment was observed when the surface energy values of the polymer were smaller than about 25 and 32 mJ/m2, respectively. Copyright © 2009 John Wiley & Sons, Ltd.

Surface properties and liquid crystal alignment behavior of poly(2-hydroxyethyl methacrylate) derivatives with alkyl ester side chains

“…This might be attributed to the effect of flexible ester connecting group which inhibit the alignment of alkyl side chains. Due to this influence of the ester group, the methylene number in the side chain of PHEMA#C for the homeotropic LC alignment is also larger than that of previously reported comb-like polymers with alkyl side chains; the homeotropic LC alignment has been reported to be observed when methylene number in the side chain is 8, 12, and 14 for poly(oxy (alkylsulfonylmethyl) ethylene), poly(alkylthiomethyl styrene), and poly(3-thiopheneacetate)/dialkyldimethylammonium complexes, respectively [18,[69][70][71]. The ester group was also found to largely affect the wetting property when PHEMA#C was in the disordered state (# 6 13), as shown in stick-slip behaviors of Fig.…”

Liquid crystal alignment behaviours on poly(methyl methacrylate) having polyhedral oligomeric silsesquioxane groups

“…Therefore, lower temperature processes using comb-like polymers, irradiating photoreactive polymers with UV light and fabricating micro-and nanostructures have been investigated to achieve the vertical LC alignment. [8][9][10][11][12][13][14] Recent investigations have demonstrated that polyhedral oligomeric silsesquioxane (POSS) materials can be used as additive materials for the vertical LC alignment system by doping the POSS materials to the LC and/or alignment layer. [15][16][17][18][19] It is not easy to reach a uniform distribution of the POSS in the LC and/or alignment layer to avoid POSS aggregation and/or agglomeration.…”

Vertical alignment of liquid crystals on plant-based vanillin derivative-substituted polystyrene films

“…For example, LC cells fabricated using nematic LC and rubbed polymer lms of n-alkylsulfonylmethyland n-alkylthiomethyl-substituted PSs having more than 8 carbons (number of alkylcarbons > 8) exhibit vertical LC alignment properties. 29 LC cells consisting of 4-alkylphenoxymethylsubstituted PSs exhibit vertical LC alignment behaviors even at a very high rubbing density of 250, regardless of the length of the alkyl side groups. 30 Vanilla attracts signicant attention as it is one of the most popular avors and improves the perception of many avors.…”