(35f) Low-Temperature Plasma Modification of Polyvinylidene Fluoride (PVDF) Membrane by Graft of Styrene in Gas

In order to control surface pore sizes of polyvinylidene fluoride (PVDF) membranes and their distribution, low temperature plasma-induced grafting modifications of PVDF were studied to prepare hydrophobe membranes. By argon (Ar) treating and subsequent grafting reaction, a hydrophobe monomer, styrene, was introduced onto PVDF membrane. FTIR was employed to characterize the chemical and physical changes of Ar plasma modified membrane; the FTIR results indicate that the graft reaction occurred on PVDF membrane surface. The surface modifications of PVDF membranes were investigated by scanning electron microscope (SEM), atomic force microscopy (AFM) and differential scanning calorimeter (DSC). It was revealed that styrene monomers were successfully grafted onto PVDF membranes. The water permeability and the solute rejection were measured by PVDF membrane modified in different graft condition. With the increasing of graft time, the pores in the modified membranes became smaller and the distribution of pores narrowed, the pure water flux decreased and the solute rejection increased.