Hydrogen Bonding is Required for Continuous Polyvinylpyrrolidone Adhesive Films

The versatility of polyvinylpyrrolidone (PVP) as a dispersing and adhesive agent lies in its amphiphilicity and hydrogen bonding capability. In this study, silicon wafers (SiO2) were silanized with N-(2-aminoethyl)-3-aminopropyltriethoxysilane (AEAPTES), (N,N-dimethylamino)trimethylsilane (TMS), and n-octyldimethylchlorosilane (C8) to construct four substrates with varying fractions of hydrogen bonding sites and hydrophobic groups. PVP thin films were fabricated on the substrates using both static adsorption and spin coating methods. PVP spontaneously adsorbs to and results in 1 nm-thick films on all the substrates, demonstrating the polymer's capability as a universal adhesive. The continuity of the dried PVP films at the nanoscopic and micron scales was imaged using atomic force and optical microscopy, respectively. The film stability was correlated to the fraction of substrate hydrogen bonding sites. The films are stable on SiO2 with 100% hydrogen bonding sites, unstable on TMS with 100% hydrophobic groups, and metastable on AEAPTES and C8 with a mixture of hydrogen bonding sites and hydrophobic groups.