Preparation Of Poly (Ionic Liquid) Brushes Via Surface-Initiated Radical Polymerization

Wettability is an important feature of surface. The main factors influencing the surface wettability are surface energy, surface roughness, and surface micro-nano structure, in which low surface energy is the basic conditions for preparing super-hydrophobic surface, surface roughness and surface micro-nano structure are decisive factors.In this thesis, some quaternary ammonium ionic liquid brushes have been successfully grafted by surface-initiated radical polymerizations on single crystal silicon surface, their surface wettability was discussed in detail.Part one: Types, physical and chemical properties, and relative application investigation advances of ionic liquids including several living radical polymerization were reviewed.Part two: Quaternary ammonium poly(ionic liquid) brushes have successfully been grafted onto silicon surface by surface initiate reverse atom transfer radical polymerization with CuCl₂/Bpy/AIBN as catalytic system and N-allyl-N,N,N-triethyl ammonium hexafluorophosphate as monomer. Surface properties of the polymer film and the polymer molecular weight are characterized by the ellipsometry,static water contact angle measurement , fourier transform infrared spectroscopy(ATR-FTIR) , X-ray photoelectron spectroscopy(XPS), atomic force microscope(AFM) and gel permeation chromatography (GPC). The results showed that the surface wettability of the poly(ionic liquid) films was closely related to the type of ionic liquids and length of the substitutes.Part three: poly(N-Allyl-N,N-dimethylbenzenaminium chloride, ADMBA-Cl) film was successfully grafted on silicon surface by NMP. The silicon surface modified with this ionic liquid showed hydrophilic. Compared with the film prepared by atomic transfer radical polymerization, this fim was more dense, smooth and homogeneous.Part four: Four kinds of quaternary ammonium ionic liquids monomers, allyltriethylamine hexafluorophosphate(ATEA-PF₆), (p-vinylbenzyl)triethylammonium hexafluorophosphate (VBTEA-PF₆), N-allyl-N,N-dimethyl-N-benzenammonium hexafluorophosphat(eADMBA-PF₆) and (p-vinylbenzyl)- N,N- dimethylbenzenaminium hexafluorophosphate(VBDMBA-PF₆) were synthesized and grafted on silicon surface The results indicated that the surface wettability of the films was closely related to the structures of the ionic liquids.