Anomaly In Stretching-Induced Swelling of Slide-Ring Gels with Movable Cross-Links
Anomaly In Stretching-Induced Swelling of Slide-Ring Gels with Movable Cross-Links
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DOI：
10.1021/ma901661d
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发表时间：
2009-11-10
期刊：
影响因子：
5.5
通讯作者：
Ito, Kohzo
中科院分区：
文献类型：
--
作者：
Murata, Naoki;Konda, Akihiro;Ito, Kohzo
研究了具有可移动交联的基于聚轮烷 (PR) 的滑环凝胶的拉伸引起的膨胀。渗透泊松比 (mu(os)) 是应变引起的膨胀的量度，针对具有不同程度的滑环迁移率的三种类型的 PR 凝胶，将其作为施加拉伸 (α(1)) 的函数进行检查。具有拓扑固定交联的经典凝胶和具有约束滑环的 PR 凝胶表现出与 alpha(1) 无关的 mu(os)。相比之下，具有高流动性滑环的 PR 凝胶表现出 alpha(1) 依赖性 mu(os)。在中等拉伸 (alpha(1) < 1.5) 的情况下，mu(os) 随着 alpha(1) 增加，而在高拉伸 (alpha(1) > 1.5) 的情况下则趋于平稳。 mu(os) 随伸长而增加是由于滑环的分子滑轮效应使变形网络的结构均质化。滑轮效应抑制由熵力引起的拉伸引起的膨胀，从而减少变形网络的构型各向异性。
Stretching-induced swelling is investigated for polyrotaxane (PR)-based slide-ring gels with movable cross-links. The osmotic Poisson's ratio (mu(os)), which is a measure of strain-induced swelling, examined as a function of imposed stretching (alpha(1)) for three types of PR gels with various degrees of the mobility of slide- rings. Classical gels with topologically fixed cross-links and PR gels with constrained slide-rings exhibit alpha(1)-independent mu(os). In contrast, PR gels with highly mobile slide-rings exhibit alpha(1)-dependent mu(os). The mu(os) increases with alpha(1) in the case of moderate stretching (alpha(1) < 1.5), whereas it levels off in the case of high stretching (alpha(1) > 1.5). An increase in mu(os) with elongation results from the molecular pulley effect of slide-rings that homogenizes the structure of deformed networks. The pulley effect suppresses the stretching-induced swelling that orginates from an entropic force to reduce the configurational anisotropy of the deformed networks.