Amphiphilic polysilane-methacrylate block copolymers: Formation and interesting properties

Several polysilane block copolymers have been prepared by the newly developed method, anionic polymerization of masked disilenes. Especially amphiphilic block copolymers of poly(1,1-dimethyl-2,2-dihexyldisilene) and poly methacrylate are focused. Poly(1,1-dimethyl-2,2-dihexyldisilene)-b-poly(2-hydroxyethyl methacrylate) (PMHS-b-PHEMA) is the first example of the amphiphilic polysilane copolymer that can form micelles in polar solvents. Poly(1,1-dimethyl-2,2-dihexyldisilene)-b-poly(methacrylic acid) (PMHS-b-PMAA) is more polar than (PMHS-b-PHEMA), soluble in water to form micelles. The cross-linking reaction of (PMHS-b-PMAA) with 1,10-diaza-4,7-dioxadecane and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride afforded the first shell cross-linked micelles (SCM) of polysilane. In addition to interesting properties, SCM is indicated to be able to form hollow sphere particles (hollow shell cross-linked micelles, HSCM) by a photochemical process. Reversible encapsulation of guest molecules by SCM and HSCM is demonstrated. Finally, SCM can be used as the template for the synthesis of metal nanoparticles, which may be used as catalysts. (Communicated by Teruaki MUKAIYAMA, M.J.A.)