Synthesis And Application Of ?,?-telechelic Polystyrenes Via Combining RAFT Polymerization And Thiol-ene "Click" Reaction

The intensive research interest was casted on the RAFT radical polymerizations, which using the dithioester as chain transfer agent (CTA) to precisely control the polymer structures and facilely tune the polymer molecular weight (Mn) and its distributions (PDI) by changing the ratio of the initial concentration of the initiator and CTA. As understanding about thiol-ene click chemistry and RAFT radical polymerizations, currently, more and more researchers focus on combining thiol click chemistry and RAFT polymerization in the preparation and modification of polymer.In this thesis, a series of well-defined a,co-telechelic polymers based on polystyrene were synthesized to study. The new a,co-telechelic polystyrene with di-and trifunctionality bearing carboxyl, (fluorinated) alkyl ester, ferrocene and single/di-allyl ester were synthesized for the first time via tandem or one-pot strategies. In a tandem procedure, polystyrene with terminal thiocarbonylthio group (PS-CTA) by RAFT polymerization was firstly synthesized using S-1-dodecyl-S'-bis(a,a'-dimethyl-a"-acetic acid)-trithiocarbonate (DDMAT) as chain transfer agent (CTA) and then transformed to ?-thiol,?-carboxyl telechelic polystyrene (HS-PS-COOH) via aminolysis with different reduction reagents such as Zn/HAc, Na2S2O4 and BU3P. Subsequently, thiol-ene "click" reaction of HS-PS-COOH with n-butyl acrylate and vinylferrocene in the presence of photoinitiator was incandescent-lamp irradiated at room temperature to achieve ?,?-telechelic PS. Moreover, a facile one-pot strategy combining aminolysis of RAFT-polystyrene and thiol-ene "click" reaction simultaneously was successfully utilized to achieve targeting diverse new a,co-telechelic polystyrene with di-and tri-functionality bearing carboxyl, (fluorinated) alkyl ester and single/di-allyl ester, i.e. combining aminolysis of PS-CTA and allyl methacrylate (AMA), 2,2,2-trifluoroethyl acrylate (TFEA),1,3,5-triallyl isocyanurate (TAIC) in the presence of photoinitiator was incandescent-lamp irradiated at room temperature to achieve ?,?-telechelic PS. The 1NMR,13C-NMR,19F-NMR, FT-IR and GPC were employed to characterize their chain structure, Mn and PDI.Three a-fluorinated alkyl ester, co-carboxyl telechelic polystyrenes (R-S-PS-COOH, R=-(CH2)2-COO-CH2-CF3,-(CH2)2-COO-CH2-(CF2)2-CF3,-CH2-CH(CH3)-COO-(CH2)2-(CF2)7-CF3) were successfully synthesized via combining aminolysis of RAFTpolystyrene and thiol-ene "click" reaction under incandescentlamp irradiation with photoinitiator. Subsequently, porous films of ?-fluorinated alkyl ester,?-carboxyl-telechelic PS were fabricated via static BF process in an aqueous vapor atmosphere, and microsphere patterns were fabricated via static BF process in methanol atmosphere. The morphology and hydrophobicity of such porous film and microsphere patterns were preliminarily investigated by scanning electron microscope (SEM), transmission electron microscopy (TEM) and water contact angle determination (WCA), respectively. We found their porous films with good regularity were fabricated via a static breath-figure process under R. H. of 95% at 30? in CS2 solution with polymer concentration of 20?40 mg·mL-1. With the change of fluorinated chain end from -CF3 to -C3F7 and -C8F17, their average pore size of ca.1.00 ?m displayed good hydrophobicity with static water-droplet contact angels of 112°,116° and 121°, respectively. Interestingly, their microsphere patterns with the average diameters 0.30,0.65 and 0.39 ?m can be fabricated using methanol instead of water as vapor atmosphere in the glass vessel, respectively.