Nanoparticle Films Constructed By Filtration Technique And Their Properties

Nanoparticle films have attracted plenty of attention in recent years due to their potential applications in magnetic records, electronic devices, catalysts and self-cleaning surfaces. In this work, we prepared nanoparticle films by filtration technique with the help of metal hydroxide nanostrands. The nanostrands were used as barrier layer and sacrificial layer. We detected the fabrication process for gold nanoparticle films, ordered macorporous gold nanoparticle films and flexible ultrathin free-standing fluorescent films. Conductivity, surface enhancement of Raman spectrum, catalytic performance and photoluminescence performance were further investigated.The contents of research are as follows:1. As thin as70nm, centimeter scale robust free-standing gold nanoparticle thin film was obtained. The thickness of the films could be easily tuned by the filtration volumes. The electronic conductivities of these films varied with the size of the gold nanoparticles, post-treatment temperature, and thickness, respectively. Furthermore, these films demonstrated an average surface Raman scattering enhancement in the order of105for Rhodamine6G molecules.2. Colloidal latex templates can be obtained in the similar method. These templates can be used to prepare ordered macroporous nanoparticle films. The pore size and the thickness of the films can be easily controlled by the templates. The robust free-standing gold nanoparticle films has potential application for electrodes, surface enhanced Raman detectors and catalyst. These templates could be extended to prepare other ordered macroporous functional nanoparticle thin films.3. We prepared flexible free-standing ultrathin protein films. The fluorescent films with different colors were obtainable by choosing fluorescent nanocrystals (and/or fluorescent dye) to be immobilized into the protein matrix. The optical properties of these films were changed with the combination of the nanocrystals and fluorescent dye. The fluorescent emission was bright, uniform which is remarkable for the application in solid optical devices.