Solution Self-assembly Of Copolymer Into Ordered Structures And Their Applications

In this dissertation,we studied the solution self-assembly of two different copolymers into ordered micellar structures and their applications,which could be divided into two parts as follows: polymer electrolyte membranes with continuous ion transfer nano-channels fabricated via solution self-assembly of polycyclooctene-graft-polyethylene glycol(PCOE-g-PEG)copolymer into micelles and followed by the incorporation of lithium salts;three-dimensional confined self-assembly of poly(4-vinylpyridine)-b-polystyrene-b-poly(4-vinylpyridine)(P4VP-b-PS-b-P4VP)copolymer within the emulsion droplets and as scaffolds to guide the arrangement of inorganic nanoparticles.The main research contents and results are summarized as follows:1.Fabrication of polymer electrolyte membranes with continuous ion transfer nano-channels: PEG-based polymer electrolyte membranes(PEMs)with continuous lithium ion transport nano-channels were fabricated by the incorporation of the PCOE-g-PEG amphiphilic copolymer self-assembled micelles and lithium salts.First,graft copolymers with different PEG contents were dissolved in common solvent and then the selective solvent for the PEG side chains was added to induce the formation of spherical micelles.Then,the micelle solutions were concentrated and lithium perchlorate(Liclo4)was added as the ion carriers.As the solvent was completely removed,the aggregations of the micelles were fussed and cross-linked together to form a free standing film after thermal treatments.Based on the above method,PEMs consisting of rather low molecular weight and low contents of PEG exhibit conductivity higher than 10-4s/cm at room temperature.This conductivity is 3 orders of magnitude higher than the films prepared by directly solvent casting method.2.Three dimensional confined self-assembly of block copolymer and co-assembly with inorganic nanoparticles: Herein,we reported the unique convex lens-like particles with lattice distributed P4 VP channels via the confined self-assembly of poly(4-vinylpyridine)-b-polystyrene-b-poly(4-vinylpyridine)(P4VP-b-PS-b-P4VP)triblock copolymers within the emulsion droplets.It is worth to note that the hexagonally packed P4 VP channels on convex lens-shaped particles can be switched on and off by changing the solvent environment.That is,the P4 VP chains could be swollen and the P4 VP channels are turned on in ethanol solvent.However,P4 VP chains will be entangled and P4 VP channels are closed off when the ethanol solvent is slowly replaced by the deionized water,which can operate as a solvent-controlled chemical gate.Moreover,the particles with well-defined nanostructure can be used as the scaffolds to guide the spatial arrangement of the gold nanoparticles(Au NPs).It is observed that the Au NPs are uniformly distributed inside the hexagonally packed P4 VP channels.