Optically and spatially templated polymer architectures formed by photopolymerization of reactive mesogens in periodically deformed liquid crystals

A unique and versatile method for forming optically (that is, orientationally) and spatially patterned polymer architectures was developed based on the photopolymerization of reactive mesogens (RMs) in a periodically deformed liquid crystal (LC). Without using lithographic or holographic implements, various polymer patterns were produced by employing nematic LCs as reaction solvents and spatially nonuniform electric fields. The nematic mixture, containing 5.0 wt.% RMs and sandwiched between patterned electrodes, was exposed to spatially uniform reaction-initiating radiation. The spatially nonuniform electric field induced periodic optical patterns in the reaction template with spatially varying elastic deformations. The resulting polymerized RM networks were both spatially and optically patterned, with good fidelity with respect to the electrode pattern and subsequent periodic director profiles. The spatial distribution of dense RM networks coincided precisely with the profile of highly deformed regions in the reaction medium. The optical birefringence of the polymer network was templated by the local director of the reaction template. Numerical calculations of director configuration and the associated elastic energy of the reaction template precisely matched the spatial and orientational order of polymerized RM networks. The proposed method provides ease and flexibility in forming organized polymer architectures for functional materials that require both positional and orientational order for their applications.