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

초록

A series of poly(methyl methacrylate) derivatives containing polyhedral oligomeric silsesquioxane (POSS) groups (MCP#) were synthesised via free radical polymerisation (FRP) using methacryl isobutyl POSS (MA-POSS) and methyl methacrylate as monomers to investigate liquid crystal (LC) alignment property of these polymer films. The LC cells made from the films of the polymers having 100mol% of MA-POSS units (MCP100) showed vertical LC alignment having a pretilt angle of about 90 degrees. The vertical LC alignment behaviour on the MCP100 film was ascribed to the very hydrophobic MCP100 surface having the surface energy value smaller than about 23mJ/m(2) generated by the nonpolar bulky POSS group. Good electro-optical characteristics, such as voltage holding ratio (VHR) and residual DC voltage (R-DC), were observed for the LC cells fabricated using MCP100 as a LC alignment layer.

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