Polymer-dispersed liquid crystals with low volume shrinkage and high peel strength based on epoxy-thiol systems

Polymer-dispersed liquid crystals (PDLCs) with low volume shrinkage and high peel strength were prepared through an epoxy-thiol click reaction catalyzed by the photogenerated base catalyst. The epoxy-thiol reaction was initiated by UV light irradiation, effectively circumventing the environmental sensitivities typically associated with conventional thermally-catalyzed polymerization processes. A systematic study was conducted to examine the impact of polymer concentration, curing temperature, polymerization light intensity and the structure of epoxy on PDLC performance. The results showed that adding a rigid epoxy structure can significantly improve the peel strength, broaden the viewing angle, and smaller the volume shrinkage. Moreover, the incorporation of 25 wt% 2,2-Bis(4-glycidyloxy-phenyl)propane into the PDLC formulation yielded PDLC with an exceptional peel strength of 50.60 N/m, volume shrinkage of 5.06%, and an expansive viewing angle having transmittance above 80% from 0° to 60°, making them highly suitable for flexible PDLC applications.

聚合物分散液晶（Polymer-dispersed liquid crystals, PDLCs）兼具低体积收缩率与高剥离强度，可通过光生碱催化剂催化的环氧-巯基点击反应制备得到。该环氧-巯基反应由紫外光辐照引发，有效规避了传统热催化聚合工艺通常存在的环境敏感性问题。本研究系统考察了聚合物浓度、固化温度、聚合光强以及环氧单体结构对PDLC性能的影响。结果表明，引入刚性环氧结构可显著提升剥离强度、拓宽视角范围并降低体积收缩率。此外，在PDLC配方中添加25质量%的2,2-双(4-环氧丙氧基苯基)丙烷，所制备的PDLC展现出优异综合性能：剥离强度达50.60 N/m，体积收缩率仅5.06%，且在0°至60°视角范围内透光率均高于80%，视角覆盖范围宽阔，非常适用于柔性PDLC应用场景。