Free-standing anisotropic side chain liquid crystalline elastomer films have been prepared using mesogens with laterally affixed polymerizable side chains. We present data on two networks:  one containing the monomer of 4‘-acryloyloxybutyl 2,5-(4‘-butyloxybenzoyloxy)benzoate and another from a 50/50 mol % mixture of the above with 4‘-acryloyloxybutyl 2,5-di(4‘-pentylcyclohexyloyloxy)benzoate. The cross-linking was achieved using 10 mol % of 1,6-hexanediol diacrylate. The calculated cross-linking density, as determined from the Young's modulus, was in the 10 -5 mol/cm3 range. Thermoelastic responses show strain changes through the nematic−isotropic phase transition to be 30−45%. The order parameters of the oriented films were determined from the dichroic ratio of IR absorption at 3343 cm-1 to the in-plane aromatic stretching overtone of the LC mesogen core. The variation of the order parameter with temperature scales similar to the strain changes at constant stress. Isostrain studies, conducted through the nematic to isotropic phase transition, show that the two networks behave as true elastomers with significant differences in the force developed. Dynamic shear measurements near the nematic to isotropic phase transition region show that the mechanical relaxation peak appears above 100 Hz, and that viscoelastic relaxations are minimal in the nematic to isotropic phase transition region below 5−10 Hz.

Zinc sulfide films were grown on carboxyl-modified polystyrene microspheres (PS-CO2) through sonochemical deposition in an aqueous bath containing zinc acetate and sulfide, released through the hydrolysis of thioacetamide. The resulting particles were “optically hollow”, due to a large refractive index contrast between the core and shell materials. Continuous, uniform films were obtained after 3−4 h and reached a maximum thickness of 70−80 nm after 13 h of growth, as characterized by transmission electron microscopy (TEM). Aggregation was minimized by subsequent modification of the core−shell particles with mercaptoacetic acid to increase their surface charge and produce good colloidal suspensions. Oscillations in the optical spectra of dilute suspensions of the particles were indicative of interference patterns as expected from Mie light scattering calculations. X-ray diffraction (XRD) patterns match the zinc blende structure of ZnS and indicate a compression in the crystal lattice (a = 5.305 ± 0.037 Å), as compared to the bulk material (a = 5.406 Å). Hollow ZnS shells were formed by annealing the core−shell particles in a thermal gravimetric analysis (TGA) oven, at 400 °C. A 34% weight loss was observed upon heating, a value approximately equal to that of the polystyrene core. The hollow shells remained intact and readily resuspended in water. Both core−shell and hollow ZnS particles self-assemble to form well-ordered, hexagonal close-packed layers.

This paper deals with the understanding at a first-principles level of the nuclear quadrupole interaction (NQI) parameters of solid chlorine, bromine and iodine as well as the intermolecular binding of these molecules in the solid. The electronic structure investigations that we have carried out to study these properties of the solid halogens are based on the Hartree-Fock Cluster approach using the Roothaan variational procedure with electron correlation effects included using many-body perturbation theory with the empty orbitals used in the perturbation theory investigations for the excited states. The results of our investigations provide good agreement with the measured NQI parameters primarily from the Hartree-Fock one electron wave-functions with many-body effects making minor contributions. The binding (dissociation) energies for the molecules with the solid state environment on 52 M.M. Aryal et al.the other hand arises from intermolecular many body effects identified as the Van der Waals attraction with one-electron Hartree-Fock contribution being repulsive in nature.