Physics – Condensed Matter – Soft Condensed Matter
Scientific paper
2009-07-17
Physics
Condensed Matter
Soft Condensed Matter
First Revision, 21 pages, 11 figures, submitted to Macromolecules as an article 17JUL2009
Scientific paper
Experimental and modeling/simulation studies of phase equilibrium and growth morphologies of novel polymer-dispersed liquid crystal (PDLC) mixtures of PS (polystyrene) and liquid crystals that exhibit a direct isotropic/smectic-A (lamellar) mesophase transition were performed for PS/10CB (decyl- cyanobiphenyl) and PS/12CB (dodecyl-cyanobiphenyl). Partial phase diagrams were determined using polarized optical microscopy (POM) and differential scanning calorimetry (DSC) for different compositions of both materials, determining both phase separation (liquid/liquid demixing) and phase ordering (isotropic/smectic-A transition) temperatures. The Flory-Huggins theory of isotropic mixing and Maier-Saupe-McMillan theory for smectic-A liquid crystalline ordering were used to computationally determine phase diagrams for both systems, showing good agreement with the experimental results. In addition to thermodynamic observations, growth morphology relations were found depending on phase transition sequence, quench rate, and material composition. Three stages of liquid crystal-rich domain growth morphology were observed: spherical macroscale domain growth ("stage I"), highly anisotropic domain growth ("stage II"), and sub-micron spheroid domain growth ("stage III"). Nano-scale structure of spheroidal and spherocylindrical morphologies were then determined via two-dimensional simulation of a high-order Landau-de Gennes model. Morphologies observed during stage II growth are typical of di- rect isotropic/smectic-A phase transitions, such as highly anisotropic "batonnets" and filaments. These morphologies, which are found to be persistent in direct isotropic/smectic-A PDLCs, could provide new functionality and applications for these functional materials.
Abukhdeir Nasser Mohieddin
Rey Alejandro D.
Soule Ezequiel R.
No associations
LandOfFree
Thermodynamics, transition dynamics, and texturing in polymer-dispersed liquid crystals with mesogens exhibiting a direct isotropic/smectic-A transition does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Thermodynamics, transition dynamics, and texturing in polymer-dispersed liquid crystals with mesogens exhibiting a direct isotropic/smectic-A transition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermodynamics, transition dynamics, and texturing in polymer-dispersed liquid crystals with mesogens exhibiting a direct isotropic/smectic-A transition will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-682990