Coating zinc oxide submicron crystals on poly(methyl methacrylate) chips and spheres via ultrasound irradiation.

Ultrasound irradiation is used for anchoring zinc oxide submicron crystals with a main diameter and length of approximately 280 nm and 470 nm, respectively, onto the surface of poly(methyl methacrylate) PMMA chips (2mm diameter), and zinc oxide crystals with a mean diameter and length of approximately 150 nm and 230 nm, respectively, onto the surface of the PMMA spheres (1-10 microm). The zinc oxide crystals were obtained by sonochemical irradiation of a mixture containing the PMMA, zinc (II) acetate dihydrate, ethanol, water, and 24 wt.% aqueous ammonia for 2h, yielding a PMMA-zinc oxide composite. By controlling the atmosphere and reaction conditions, we could achieve well-adhered zinc oxide crystals on the surface of poly(methyl methacrylate). The resulting zinc oxide-PMMA composite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray analysis (EDX), high-resolution scanning electron microscopy (HRSEM), and photoluminescence (PL) spectroscopy. The zinc oxide-deposited PMMA chips (loaded with 0.03-1.0 wt.% ZnO) were successfully homogenized in melt by extrusion and then injection molded into small, disc-shaped samples. These samples were analyzed with respect to their directional spectral optical properties in UV, Vis and IR spectroscopy.