Structural and Quantitative Analysis of Surface Modified Poly(vinylidene Fluoride) Films Using ATR FT-IR Spectroscopy

Abstract

The reaction of PVF₂ films in aqueous NaOH with the use of tetrabutylammonium hydrogen sulfate as phase transfer catalyst results in surface dehydrofluorination. Subsequent examination of the PVF₂ surface using ATR FT-IR affords evidence as to the structure of dehydrofluorinated PVF₂. It is found that the infrared bands at 1402, 1225, 1194, and 882 cm⁻¹ are sensitive to the surface treatment. The origin and behavior of these bands are discussed. It is observed that upon dehydrofluorination the FT-IR spectra of the PVF₂ surface exhibit two infrared bands at 1613 cm⁻¹ and 1717 cm⁻¹ which arise from the formation of carbon-carbon double bonds. The band at 1613 cm⁻¹ is due to conjugated -(-CH=CF-)- units, whereas the 1717 cm⁻¹ band is assigned to the -(-CF=CF-)- units which arise from resonance at structural head-to-head and tail-to-tail defects.