In this study, by using 2,2,3,4,4,4-hexafluorobutyl methacrylate (HFMA) and a synthesized side methacryloxy group polysiloxane (MAPS) as modifying materials and bisphenol-A epoxy methacrylate (BEMA) as matrix,
respectively, a innovative UV-curing system, BEMA/HFMA/MAPS composite system was developed. Through UV-cure process, a series of BEMA/HFMA, BEMA/MAPS, and BEMA/HFMA/MAPS cured composite films with different proportions were successfully obtained. It was found that HFMA monomer was helpful for the reduction of the surface energy of the UV-cured composite films and the enhancement of their water resistance property. Without HFMA in BEMA matrix, MAPS could facilitate the improvement of the properties of BEMA/MAPS MK-4827 concentration cured films, and the presence of MAPS in BEMA/HFMA/MAPS system could significantly decrease the surface energy of the cured films to 22.1 mJ/m(2) and improve their thermal stabilities and water resistance properties by measurements, contact angle, TGA, DSC, and water resistance. To the SEM observation, HFMA and MAPS were well distributed in the cured films in favor of their excellent performances. (C) 2010 Wiley Periodicals, Inc. J Appl SBE-β-CD in vitro Polym Sci 117: 1859-1866, 2010″
“In this study, photoluminescence (PL) under high excitation intensity as a function of crystalline size was systematically investigated
through ZnO nanocrystalline films prepared by spin-coating a colloidal solution of ZnO nanoparticles obtained using the microemulsion method. Annealing of the films at 723, 633, and 593 K allowed us to
tune the crystalline radius R. PL studies distinguished different regimes of crystalline size according to the ratio of R to the effective Bohr radius a(B)(R/a(B)). For the sample annealed at 723 K (R/a(B)=7.2), the peak of stimulated emission due to the exciton-exciton collisions appeared on the low-energy side of the exciton emission with an increase in excitation intensity. Z-DEVD-FMK A further increase in excitation intensity eventually resulted in the occurrence of an electron-hole plasma (EHP) accompanied by consequent band gap renormalization, which indicates that high excitation intensity provokes the dissociation of excitons. For the sample annealed at 633 K (R/a(B)=4.7), the stimulated emission was observed while the transition to EHP was obscure. For the sample annealed at 593 K (R/a(B)=2.1), only emissions due to the recombination of the electron-hole pair were observed, and stimulated emission did not appear even when the excitation intensity was increased. The transition from free-exciton emission to donor-bound exciton emission was observed in temperature dependence of PL only for the sample with R/a(B)=7.2. The origin of annihilation of the stimulated emission with a size reduction is discussed based on nonradiative Auger recombination. (C) 2010 American Institute of Physics. [doi:10.1063/1.