Synthesis and Self-assembly of Novel Amphiphilic Copolymers containing POSS moiety

摘要

1.Introduction Over the last decade the chemistry of polyhedral oligomeric silsesquioxanes (POSS) has drawn much attention due to the ability of this class of compounds to act as well-definod nanostructured building blocks for organic-inorganic hybrid materials [1-3]. POSS units are three-dimensional, cube-shaped species with diameters ranging between 1 and 3 nm, characterized by an inorganic inner siloxane core (SiO1.5)x surrounded by organic substituents. The incorporation of POSS moiety into polymers can lead to hybrid organic-inorganic nanocomposites and dramatically improve the polymer properties such as lower surface energy, reduction in flammability, surface hardening and so on[2]. Especially the combination of closed cage POSS group and poly (ethylene oxide) (PEO) have attracted more scientific interest, because amphiphilic polymers due to the nanophase-separated structure can self-assemble into various morphologies of nanostructured materials with some unique properties, which are expected to have promising applications in many fields. Wunder et al [4] prepared an inorganic-organic nanocomposite with amorphous biphasic structures from an amphiphilic block copolymer, POSS-PEO, and LiClO4 and found that the nanocomposite was a good battery material with a low Tg and a higher conductivity. Cho et al. [5] reported that nanostructured polyurethane materials were obtained from the block copolymers of POSS and PEO which showed an interesting property of water-responsive shape memory. Isayeva and Kennedy [6] found that a crosslinked membranes composed of PEO, POSS, and poly (dimethylsiloxane) possessed good mechanical properties and high oxygen permeability.