1 research outputs found
Role of Monomer Alkyl Chain Length in Pretilt Angle Control of Polymer-Stabilized Liquid Crystal Alignment System
The
pretilt angle of liquid crystal (LC) molecules in LC cells
was manipulated by adding a mixture of two photocurable monomers,
alkyl acrylate and biphenyl diacrylate, into the LCs after the UV
treatment. The hexyl acrylate and octadecyl acrylate were applied
to examine the alkyl chain length effect on the pretilt angle control
under the condition of a fixed concentration of biphenyl diacrylate.
The LC alignment was continuously adjusted from homogeneous to homeotropic
alignment in the polymer-stabilized LC system by simply increasing
the alkyl acrylate concentration in the LCs. At a given molar concentration
of alkyl acrylate, the addition of octadecyl acrylate exhibits higher
pretilt angle than that of hexyl acrylate. Both the pretilt angle
of the LCs and advancing contact angle of water on the inner surfaces
of LC cells simultaneously changed due to surface chemical nature
and surface roughness. The pretilt angle increases along with an increase
in the advancing contact angle. As a consequence, the surface advancing
contact angle acts as an index for pretilt angle control