Synthesis And Solution Properties Of Amphiphlic Block Copolymers Consisting Of Polysiloxane And Poly(Ethylene Oxide)

As a very potential method to prepare advanced materials of specific functionality,especially for the preparation of functional materials with desired structure and size(nanometers to micrometers),self-assembly behavior has attracted a lot of research attention.Amphiphilic block copolymers in solution self-assemble into a variety of structures,e.g.,spherical,rod-like,vesicles,lamellae and micelles with more complicated structures.Amphiphilic block copolymers have a large potential in a wide range of technical applications.Different from ordinary surfactants,the structure of self-assembled aggregates with amphiphilic copolymers can be controlled by choosing proper blocks and appropriate structure of the block copolymers.In this dissertation,polysiloxane(and fluoro-containing polysiloxane) and poly(ethylene oxide) were chosen respectively as the hydrophobic and hydrophilic block.Si-H end-functionalized poly(dimethylsiloxane)(PDMS) was synthesized via anionic ring open polymerization of octamethylcyclotetrasiloxane(D₄) initiated by acid treated bentonite.And start with the PDMS synthesized,poly(ethylene oxide)-b-poly(dimethylsiloxane)-b-poly(ethylene oxide)(PEO-b-PDMS-b-PEO) and [poly(dimethylsiloxane)-b-poly(ethylene oxide)]n([PDMS-b-PEO]n) with varing ratios of DMS to EO segments were synthesized by hydrosilation coupling reaction of the Si-H end-functionalized polysiloxane and different kind of allyl-terminated polyethyleneoxide.The phase behavior of the resulting PDMS/PEO block copolymers was investigated with Surface Tensiometer,proton Nuclear Magnetic Resonance (¹H-NMR) and Transmission Electro Microscopy(TEM),depending on the proportion of different blocks,concentration,solvent,staying time.Morphology transition was detected and primitive explanations were given accordingly.