No abstract

We demonstrate light-induced formation of semiconductor quantum dots in TOPAS® polymer matrix with very high control of their size and their spatial localization. Irradiation with UV laser pulses of polymer films embedding Cd thiolate precursors results in the formation of cadmium sulfide nanocrystals well confined in the irradiation area, through a macroscopically nondestructive procedure for the host matrix. With increasing number of laser pulses, we accomplish the formation of nanoparticles with gradually increasing dimensions, resulting in the dynamic change of the spectra emitted by the formed nanocomposite areas. The findings are supported by x-ray diffraction and transmission electron microscopy measurements.

We demonstrate the wetting behavior control of polymer surfaces doped with photochromic molecules by modifying the surface patterning features introduced by soft molding lithography. Such surfaces enhance their hydrophilicity upon UV irradiation due to conversion of the non-polar spiropyran dopant molecules to their polar merocyanine isomers. The process is reversed upon visible light irradiation. By changing the topological parameters of the introduced pattern, one achieves surface tuning from hydrophobic to hydrophilic situations. The difference for the contact angles between UVand green-irradiated surfaces may become significantly higher than for the flat surfaces, for the specific patterning parameters analyzed.