Orientational and Structural Transitions of Semiflexible Polysilanes on the Surfaces

Control of conformation, orientation, and topology of chain-like polymers on surfaces has been a longstanding issue because both the proper models and detection systems with ultrahigh sensitivity and high accuracy have not existed. Among various chain-like polymers, soluble organopolysilane (PSi) is a suitable model for elucidating the uniqueness of chain-like polymers on the surfaces because of their tunable molecular length, adjustable polydispersity, stiffness, and presence of terminal groups by adequate molecular design, careful synthesis, and purification. Furthermore, PSi is a highly luminescent chromophore due to Si sigma-Si sigma* transition of the Si main-chain. This comprehensive paper covers our recent works on (1) tethering of PSi on surfaces with a silane coupling reaction, (2) orientational phase transition of self-assembled PSi monolayer, and (3) structural phase transition of isolated PSi chain.