Study On The Microphase Separation And Surface Properties Of Block Copolymers Of Fluorosilicone With Vinyl Monomers

Fluorosilicone polymer has excellent physical and chemical properties,such as low surface energy,solvent resistance,and so on.The important feature of block copolymer is that the block copolymers could form ordered spherical,cylindrical,lamellar and other microphase-separated structures by self-assembly.However,the relationship between microstructure and surface properties of the block copolymers of fluorosilicone and vinyl monomers was not clear until now.By studying the microstructure and surface properties of the block copolymers of fluorosilicone and vinyl monomers,the relationship between microstructure and surface properties of the block copolymers could be obtained and some theoretical knowledge could be provided for the application of fluorosilicone copolymers.In this paper,block copolymers of fluorosilicone and vinyl monomer are synthesized by atom transfer radical polymerization(ATRP),using poly[methyl(3,3,3-trifluoropropyl)siloxane](PMTFPS)as fluorosilicone segment,and polymethyl methacrylate(PMMA)or polystyrene(PS)as the vinyl monomer segment.And then,the microstructure and the surface properties of the block copolymer were investigated in this work.The main results are shown as follows:1.By the anionic polymerization,functionalization reaction of end group,and atom transfer radical polymerization(ATRP),a series of PMTFPS-b-PMMA and PMTFPS-b-PS block copolymers were synthesized in this work.(1)By anionic ring-opening polymerization of a monomer to F3,followed by hydrosilylation reaction and esterification reaction,a series of PMTFPS-Br were synthesized with different degrees of polymerization.(2)Well-architectured PMTFPS-b-PMMA or PMTFPS-b-PS diblock copolymers were obtained via the ATRP of MMA or St by using PMTFPS-Br as the ATRP macroinitiators.2.The microphase separation of PMTFPS-b-PMMA or PMTFPS-b-PS diblock copolymers were conformed.(1)Differential scanning calorimetry(DSC)test results show that PMTFPS-b-PMMA or PMTFPS-b-PS diblock copolymers can show clear microphase-separated structures.But the glass transition temperature of fluorosilicone segment is not clear because the length of fluorosilicone segment is too short.(2)Transmission electron microscopy(TEM)and small angle X-ray scattering(SAXS)analysis results show that the block copolymers can form cylindrical microstructure.3.The relevant information of surface morphology and surface properties of PMTFPS-b-PMMA or PMTFPS-b-PS block copolymer were obtained.(1)X-ray photoelectron spectroscopy(XPS)results show that the fluorine content on the surface of PMTFPS-b-PMMA diblock copolymers is higher than that of PMTFPS-b-PS diblock copolymers with a similar composition.By an ion etching on the PMTFPS-b-PMMA coating,the result shows the content of fluorine is decreasing with the increase of etching depth.(2)Atomic force microscopy(AFM)results show the surfaces of PMTFPS-b-PMMA and PMTFPS-b-PS block copolymer coatings are relatively smooth and the surface roughness are between 8-12 nm.But the surface roughness of PMTFPS-b-PMMA coating is larger than that of PMTFPS-b-PS with a similar composition.(3)Contact angle measurement(CAM)results show the surface energy of PMTFPS-b-PMMA or PMTFPS-b-PS block copolymer are lower than 27 mN/m.However,the water contact angles on PMTFPS-b-PMMA are higher than that of PMTFPS-b-PS with a similar composition.But the contact angle of methylene iodide on the surface of PMTFPS-b-PS are larger than that of PMTFPS-b-PMMA with a similar composition.