ZHANG Puyu, LIU Yang, PENG Lichao, GUO Yougang. SYNTHESIS OF PSt-b-PAA-b-PSt AMPHIPHILIC BLOCK COPOLYMERS VIA RAFT POLYMERIZATION AND THEIR SELF-ASSEMBLY IN IONIC LIQUID [BMIM][PF6]. [J]. Acta Polymerica Sinica (1):59-64(2010)
DOI:
ZHANG Puyu, LIU Yang, PENG Lichao, GUO Yougang. SYNTHESIS OF PSt-b-PAA-b-PSt AMPHIPHILIC BLOCK COPOLYMERS VIA RAFT POLYMERIZATION AND THEIR SELF-ASSEMBLY IN IONIC LIQUID [BMIM][PF6]. [J]. Acta Polymerica Sinica (1):59-64(2010) DOI: 10.3724/SP.J.1105.2010.00059.
SYNTHESIS OF PSt-b-PAA-b-PSt AMPHIPHILIC BLOCK COPOLYMERS VIA RAFT POLYMERIZATION AND THEIR SELF-ASSEMBLY IN IONIC LIQUID [BMIM][PF6]
The Block copolymer polystyrene-b-poly(acrylic acid)-bpolystyrene (PSt-b-PAA-b-PSt) was synthesized via reversible addition-fragmentation chain transfer polymerization by using styrene as the first monomer.The architectures of the macro-chain transfer agent PSt-CTA and the block copolymers were confirmed by FTIR and 1H-NMR.GPC analysis was used to estimate the molecular weight and the molecular weight distribution of the copolymers
the numeraverage molecular weight of macro-chain transfer agent PSt-CTA was 8320
and the molecular weight distribution was 1.05.The numer-average moleccular weight of three block copolymers was 13050
11130 and 9760
respectively
and the corresponding molecular weight distribution was 1.356
1.430
1.365.The block copolymers with different molecular weights were self-assembled by co-solvent method in an ionic liquid
1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]).The nanostructures of the PSt-b-PAA-b-PSt micelles formed in the ionic liquid were observed by TEM (transmission electron microscopy) and DLS(dynamic light scattering).The self-assembled morphologies of the copolymers are strongly dependent on the length of PAA block chains when the chain length of PSt is fixed.With the decrease of molecular weight of PAA in block copolymers
the resulting aggregates are spheres with diameter of about 50 nm.With further decrease of PAA molecular weight in copolymers
the sphere morphology is turned to core-shell sphere micelles with diameters not more than 100 nm.Compared with the aqueous solutions of the same copolymers
[BMIM][PF6] solutions exhibit some distinct features
such as temperatureindependent micellar morphologies between 25℃ and 100℃.