Fabrication of highly efficient coatable polarizer from tolane-based smectic reactive mesogen

• Published in: Polymer (Guilford) Vol. 176; pp. 51 - 59
• Main Authors: He, Rui, Oh, Enche, Ye, Yang, Wen, Pushan, Jeong, Kwang-Un, Lee, Seung Hee, Li, Xiang-Dan, Lee, Myong-Hoon
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 02-08-2019; Elsevier BV
• Subjects: Additives; Alignment; Coatable polarizer; Corrosion resistance; Dichroism; Dyes; Fabrication; Host-guest system; In-situ polymerization; Irradiation; Mechanical properties; Organic light emitting diodes; Photopolymerization; Polarization; Polarizers; Reactive mesogen; Smectic phase; Spin coating; Substrates; Thermal resistance; Thermal stability; Ultraviolet radiation; Coatable polarizer; In-situ polymerization; Host-guest system; Smectic phase; Reactive mesogen
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2019.05.032

This work is aimed to fabricate ultra-thin coatable polarizers on a single substrate based on “host-guest” effect between highly ordered smectic reactive mesogen (RM) and dichroic dye. We designed and synthesized a new tolane-based RM with a highly ordered smectic A phase at room temperature. Polymerizable “host-guest” mixture was formulated from the host RM, dichroic dye and additives, then spin-coated on a single substrate having an alignment layer. Subsequent in-situ photopolymerization by UV irradiation successfully resulted in a coatable polarizer with good polarizing properties. The fabricated coatable polarizer showed a dichroic ratio (DR) of 16.4 and a degree of polarization (DOP) of 99.3% with the thickness of 4 μm. The resulting coatable polarizer possessed a considerable solvent resistance, good thermal stability and robust mechanical properties. Moreover, we prepared a TN-mode LC cell by using the prepared coatable polarizers inside the cell (in-cell), in which the coatable polarizers acted as a polarizer and an alignment layer, simultaneously. The resulting TN cell with in-cell polarizers exhibited a decent electro-optical behavior. We believe that the coatable polarizer proposed in this study possesses practical application potential in ultra-thin LCDs or flexible OLEDs.
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•Reactive mesogen with smectic A phase was synthesized for coatable polarizer.•Coatable polarizer was fabricated on a single substrate by “host-guest” method.•Coatable polarizer exhibits considerable optical property and excellent stability.•LCD with in-cell structure was demonstrated by using the prepared coatable polarizer.