Synthesis And Application Of Photoacid Generator(PAG) And PAG-containing Acid-sensitive Polymers

The use of light irradiation is particularly attractive due to its easy operation,low cost,non-invasive nature,remote controllability,high spatial resolution,and temporal precision.Recently,photoacid generators(PAGs)have deserved special at-tention due to their applications in a wide range of areas including biological probing,controlling enzyme activity,oxygen inhibition,photodynamic therapy,protecting group chemistry,polymerization initiation,and in the preparation of adhesives and inks.Sulfonium PAGs have attracted increasing interest because they can easily pro-duce H~+upon irradiation and used to activate a wide variety of reactions including the ring opening of oxetanes and epoxides.In this paper,a photoacid generator4(methacryloyloxy)-phenyl)dimethyl sulfonium triflate(MAPDST)was synthesized,which was used to copolymerize with an acid-cleavable monomer((2,4,6-trimethoxybenzylidene-1,1,1-tris(hydroxymethyl)ethane methacrylate,TTMA)and hydrophilic monomer poly(ethylene glycol)methyl ether methacrylate(PEGMA)for preparation of functional photo-controlled acid-sensitive polymer poly[poly(ethyleneglycol)methylethermethacrylate-co-4(methacryloyloxy)-phenyl)dimethylsulfoniumtriflate-co-(2,4,6-trimethoxybenzylidene-1,1,1-tris(hydroxymethyl)ethane methacrylate][P(PEGMA-co-MAPDST-co-TTMA)]with different hydrophobic-hydrophilic ratios by two-steps reversible addition fragmentation chain transfer(RAFT)copolymeriza-tion.Nuclear magnetic resonance(~1H-NMR)and Fourier transform infrared spec-troscopy(FT-IR)was used to determine the molecular structures and chemical com-positions of P(PEGMA-co-MAPDST-co-TTMA).Transmission electron microsco-py(TEM)and scanning electron microscopy(SEM)was used to investigate the mor-phology of self-assembled nanostructures of P(PEGMA-co-MAPDST-co-TTMA).Furthermore,due to the presence of PAG,the hydrophobic TTMA chain could be se-lectively hydrolyzed into a hydrophilic backbone in the mildly acidic environment due to UV irradiation,leading to significant swelling and final disassembly of the nanoparticles.Thus these results may be helpful for the development of pho-to-controlled acid-sensitive polymer and corresponding photo-sensitive functional nanomaterials.