Cationic salt-responsive bottle-brush polymers.
Cationic salt-responsive bottle-brush polymers.
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DOI：
10.1002/marc.201300088
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发表时间：
2013-04
影响因子：
4.6
通讯作者：
Kejian Yao;Ying Chen;Jun Zhang;C. Bunyard;Chuanbing Tang
中科院分区：
文献类型：
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作者：
Kejian Yao;Ying Chen;Jun Zhang;C. Bunyard;Chuanbing Tang
制备了一类具有离子强度依赖性刺激响应性的阳离子瓶刷聚合物。通过开环复分解聚合、开环聚合和点击反应的组合合成了以降冰片烯为主链、含季铵（QA）的聚己内酯共聚物为侧链的刷状聚合物。在低离子强度的水中，由于阳离子QA基团之间的强静电排斥力，刷状聚合物是可溶的。随着盐的添加以增加离子强度，单刷聚合物经历从扩展构象到塌陷状态的转变，并最终由于盐的屏蔽作用而变得不溶于溶液，导致QA物种之间一度占主导地位的静电相互作用转变为疏水-疏水相互作用。
A class of cationic bottle-brush polymers that show ionic strength-dependent stimuli responsiveness is prepared. Brush polymers with norbornene as backbone and quaternary ammonium (QA)-containing polycaprolactone copolymers as side chains are synthesized by a combination of ring-opening metathesis polymerization, ring-opening polymerization, and click reaction. In water with low ionic strength, brush polymers are soluble due to the strong electrostatic repulsion between cationic QA groups. As the addition of salt to increase ionic strength, single brush polymers undergo a transition from extended conformation to collapsed state and finally become insoluble in solution due to the screening effect of salts that yield the once-dominant electrostatic interactions among QA species to hydrophobic-hydrophobic interactions.