Flexible and Patterned Thin Film Polarizer: Photopolymerization of Perylene-based Lyotropic Chromonic Reactive Mesogens

Abstract

A perylene-based reactive mesogen (DAPDI) forming a lyotropic chromonic liquid crystal (LCLC) phase was newly designed and synthesized for the fabrication of macroscopically oriented and patterned thin film polarizer (TFP) on the flexible polymer substrates. The anisotropic optical property and molecular self-assembly of DAPDI were investigated by the combination of microscopic, scattering and spectroscopic techniques. The main driving forces of molecular self-assembly were the face-to-face π-π intermolecular interaction among aromatic cores and the nanophase separation between hydrophilic ionic groups and hydrophobic aromatic cores. Degree of polarization for the macroscopically oriented and photopolymerized DAPDI TFP was estimated to be 99.81% at the λmax = 491 nm. After mechanically shearing the DAPDI LCLC aqueous solution on the flexible polymer substrates, we successfully fabricated the patterned DAPDI TFP by etching the unpolymerized regions selectively blocked by a photomask during the photopolymerization process. Chemical and mechanical stabilities were confirmed by the solvent and pencil hardness tests, and its surface morphology was further investigated by optical microscopy, atomic force microscopy, and three-dimensional surface nanoprofiler. The flexible and patterned DAPDI TFP with robust chemical and mechanical stabilities can be a stepping stone for the advanced flexible optoelectronic devices.

Multifunctional Optical Thin Films Fabricated by the Photopolymerization of Uniaxially Oriented Lyotropic Liquid Crystal Monomers for Electro-Optical Devices

“…High yield and purity are confirmed by the proton ( 1 H) nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization mass spectroscopy (ESI-MS). The concentration of the PBRM in aqueous solutions is varied between 25 and 75 wt% in the presence of the 1 wt% water-soluble photo-initiator31. The PBRM MOTF is simply fabricated by the mechanical shear coating on the indium-tin oxide (ITO)-coated glass and the subsequent photopolymerization (see Supplementary Fig.…”

“…The phase transition of PBRM-H 2 O with respect to temperature and concentrations was fully estimated in our previous work31 and it is summarized in Fig. 1.…”

“…Upon increasing the temperature of PBRM-H 2 O solutions between 10 and 30 wt%, the Col N phase transforms to the I phase by passing the biphase (Col N  + I) region. It is worth noticing that the formation of biphase between Col N and I phases is one of the typical characteristics of LCLC compounds31. For the fabrication of macroscopically oriented PBRM MOTF, the concentration of PBRM solution is fixed to be 25 wt%, which is optimized based on the results of POM morphological observations and degree of polarization (DOP).…”

“…Recently, our research group successfully fabricated the coatable thin film polarizer by the polymer-stabilization of macroscopically oriented lyotropic chromonic liquid crystal (LCLC)28293031. The LCLC-based coatable polarizers stabilized by the photopolymerization of LCLC monomers exhibit high polarizabilities as well as excellent chemical and mechanical resistances.…”

“…It is worth noticing that the LCLC-based coatable thin film is a E-type polarizer which transmits the extraordinary ray and extincts the ordinary ray, while the conventional polarizer using the stretched-polymer is a O-type polarizer which transmits the extraordinary ray and extincts the ordinary ray. Thus, the incident light polarized parallel to the long molecular axis of the LCLC molecule can transmit the polarizer29303132333435.…”