Gold-nanoparticle- and gold-nanoshell-induced polymorphism in poly(vinylidene fluoride)

PVDF nanocomposites are prepared through solution mixing of Au-NPs or Au-NSs with PVDF. The novel optical properties of Au-NPs and -NSs are retained as confirmed from UV-Vis spectra. Analysis of resulting nanocomposites by FT-IR, XRD, and DSC shows an obvious polymorphism change from α- to β-form compared to PVDF prepared under the same conditions. The β-polymorph seems to be more prominent with higher concentration of Au-NPs (0.5%) and even more so with Au-NSs. Thermogravimetric analysis shows that both nanocomposites have better resistance toward thermal degradation. Combination of novel optical properties of Au-NPs or Au-NSs with induced ferroelectric-active β-polymorph in PVDF can lead to new design of optical, piezoelectric devices. Incorporation of gold nanoparticles and nanoshells into poly(vinylidene fluoride) brings novel optical properties into the host polymer, induces a polymorphism transformation toward the ferroelectric-active β-phase, and retards the thermal degradation of materials. The combined optical and ferroelectric characteristics of these nanocomposites can lead to new optical and piezoelectric devices.