Unusual effect of molecular weight and concentration on thermoresponsive behaviors of well‐defined water‐soluble semirigid polymers
Unusual effect of molecular weight and concentration on thermoresponsive behaviors of well‐defined water‐soluble semirigid polymers
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DOI：
10.1002/pola.26158
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发表时间：
2012-09
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影响因子：
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通讯作者：
Peng Liu;He-Lou Xie;Haoyu Tang;G. Zhong;Hailiang Zhang
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文献类型：
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作者：
Peng Liu;He-Lou Xie;Haoyu Tang;G. Zhong;Hailiang Zhang
采用可逆加成断裂链转移（RAFT）聚合法，合成了一系列基于介晶夹套液晶聚合物（MJLCP）的水溶性半刚性温敏聚合物聚[双（N-羟基异丙基吡咯烷酮）-2-乙烯基对苯二甲酸酯]（PHIPPVTA）。动态光散射（DLS）显示，新型单体和聚合物具有温敏特性，浊点在10 ° C至90 °C之间。当聚合物分子量从0.47 × 104 g mol−1增加到3.69 × 104 g mol−1时，浊点增加了56.2 °C。此外，随着聚合物浓度从5增加到10 mg mL-1，PHIPPVTA的浊点降低了18.8 °C。在敲除PHIPPVTA的端基后，观察到浊点略微增加（0.1-3.5 °C）。此外，与其他柔性主链温敏聚合物相比，无论是否含有三硫代碳酸酯端基，其浊点均随分子量的增加而增加，且呈现相反的趋势。这些聚合物显示出显着的溶剂同位素效应，在D2 O的浊点低于在H2O。© 2012 Wiley Periodicals，Inc. J Polym Sci Part A：Polym Chem，2012
A series of water-soluble semirigid thermoresponsive polymers with well-defined molecular weights based on mesogen-jacketed liquid crystal polymers (MJLCPs), poly[bis(N-hydroxyisopropyl pyrrolidone) 2-vinylterephthalate] (PHIPPVTA) have been synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization. Dynamic light scattering (DLS) revealed that the novel monomer and polymers have thermoresponsive properties with cloud point in the range between 10 and 90 °C. The cloud point was increased by 56.2 °C when the polymer molecular weight increased from 0.47 × 104 g mol−1 to 3.69 × 104 g mol−1. In addition, the cloud point of PHIPPVTA was decreased by 18.8 °C with the increase of polymer concentration from 5 to 10 mg mL−1. A slight increase (0.1–3.5 °C) of cloud point has been observed after knocking off the end-groups of PHIPPVTA. Moreover, the cloud point of polymer increased with increasing of its molecular weight with or without the trithiocarbonate end-groups, which showed the opposite trend comparing with other thermoresponsive polymers with flexible backbones. These polymers show a dramatic solvent isotopic effect that the cloud point in D2O was lower than in H2O. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012