MesoScale Morphology Development in PDLCs: Real-Time Synchrotron Small Angle X-ray Scattering Studies
Abstract
Simultaneous real-time curing / small angle X-ray scattering were utilized to examine the nano (1-100 nm) and meso (100-1000 nm) scale morphology development of polymer dispersed liquid crystal (PDLC) films. In contrast to conventional PDLCs derived from photo-initiated step-growth polymerizations, these PDLC films were formed using photo-irradiation of initially homogeneous syrup comprised of highly functional free-radical monomer and liquid crystal, resulting in rapid molecular weight increase and network formation prior to or in conjunction with phase separation. Two-phase morphology via HRSEM was absent below 20wtfluctuations in LC concentration and network crosslink density at all LC concentrations, implying complex hierarchical morphology comprised of discrete LC domains as well as fluctuations in network cross-link density and local LC concentration. The features and their temporal evolution depend on incident intensity and concentrations of co-additives. An understanding of the dependence on polymerization mechanism in controlling the type and form of two-phase morphology in PDLCs is critical to optimize morphology and thus system performance.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2002
- Bibcode:
- 2002APS..MAR.J2004V