| Layered polymeric structures made via forced assembly have shown unique optical, mechanical, electrical and barrier properties. The advantages include the flexibility of the process in scaling from macro to nano scale; and the ability to incorporate electrically/optically active small molecules.; Excellent control over the cell size is demonstrated in PP foam/film structures. Cell size can be reduced considerably by increasing the number of layers without adversely affecting the density. The cell structure and the compressive response of these structures is similar to Cork. The tensile and compressive moduli could be predicted using series and parallel composite models. The constituent materials can be chosen to alter the flexibility of the composite.; Narrowband 1D photonic crystals have been fabricated using microlayer coextrusion. Assemblies of 128 alternating polystyrene and polymethyl methacrylate layers were successfully made that demonstrated the tuning of the photonic band gap. The structural perfection of the photonic crystals was evaluated via model simulations and atomic force microscopy.; Alternate layers of a 1D photonic crystal could be doped with an optical limiting dye and{09}scaling of the layers could be adjusted so as to enhance the optical limiting effect with the layer reflectivity. A prerequisite for this is achieving dispersion of dye molecules in the monomer form. Aggregation studies of PbPc(beta-CP)4 were carried out with blends in polycarbonate using the UV-VIS spectroscopy. An attractive feature of the polycarbonate blends is the high concentration of monomer. The concentration effect is satisfactorily described by the monomer/dimer equilibrium.; Solid state structure of these blends was probed. In the concentration range 0 to 0.1%, monomer fills up large free volume holes in polycarbonate, as indicated by the sharp increase in density and refractive index. Between 0.1 to ∼8%, PbPc(beta-CP)4 is mostly in monomer form. Monomer "antiplasticizes" polycarbonate, resulting in reduced glass transition temperature, increased modulus and suppression of the sub-Tg gamma relaxation for polycarbonate. The refractive index-density relationship can be described by the Lorenz-Lorenz equation. Above ∼ 8 %, formation of aggregates is detected. The densification of the blends are attributed to the combined effect of reduction in free volume; and the addition of PbPc(beta-CP) 4. |
