methods for preparing functionalized polyvinylpyrrolidones with polymerizable functions . also , amphipathic polydimethylsiloxane - pvp block copolymers , such as and acrylated and acrylamide - functionalized polyvinylpyrrolidone compounds , such as the block copolymers are useful as biomaterial components in biomedical devices . they provide improved wettability , lubricity , and material compatibility to the biomedical device , e . g ., ophthalmic lenses .