Capillary Wrinkling of Nanocomposite Films

We have investigated morphology and capillary wrinkling of PS-SH M_w 124k chemisorbed on 12 nm (diameter) of Gold Nanoparticles (GNPS) in PS M_w 97k matrices with various weight fractions (0%, 5%, 9% 13%) of the GNPS. The PS chemisorbed GNPS were uniformly dispersed in the PS M_w 97k matrices even if the weight fraction of GNPS increased up to 13%, determined by AFM micrographs. Various thicknesses (30 to 300 nm) of nanocomposites were floated on water. A water droplet was applied on the floating nanocomposite film to induce hoop compression, resulting in the radial wrinkle patterns on the film [1]. As the weight fraction of the GNPS increases, the length of wrinkle increases while the number of wrinkle decreases, regardless of the thickness of the nanocomposite films. This indicates the Young’s modulus of the composites increases twice with the addition of GNPS from 0 to 13 wt%.

[1] Science 2007, 317(5838), 650-653