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Pronounced effects of the densities of threaded rings on the strain-dependent Poisson's ratio of polyrotaxane gels with movable cross-links
Soft Matter ( IF 3.4 ) Pub Date : 2018-03-22 00:00:00 , DOI: 10.1039/c8sm00257f
Akira Tanaka 1, 2, 3, 4, 5 , Kazuaki Kato 6, 7, 8, 9, 10 , Kohzo Ito 6, 7, 8, 9, 10 , Kenji Urayama 1, 2, 3, 4, 5
Affiliation  

The density of threaded ring molecules (fCD) in polyrotaxane (PR) chains has pronounced effects on the strain-induced swelling of PR gels where the cross-linked ring molecules are slidable along the network strands. The equilibrium Poisson's ratio (μ), which is a measure of the strain-induced volume change, for the PR gel increases with an increase in elongation (λ) at moderate λ but becomes a constant value (Image ID:c8sm00257f-t1.gif) at sufficiently large λ. When the modulus exceeds a threshold value (Ec), the λ dependence of μ disappears due to the loss of the slidability of the cross-links. The fraction fCD significantly influences the values of Image ID:c8sm00257f-t2.gif and Ec. When fCD is sufficiently small (<14%), Image ID:c8sm00257f-t3.gif (≈0.25) agrees with the values of μ for the classical gels in good solvents. When fCD is high (>25%), Image ID:c8sm00257f-t4.gif varies over a wide range (0.22 < Image ID:c8sm00257f-t5.gif < 0.33) depending on fCD and the cross-link concentration in a complicated way. The modulus Ec at fCD = 25% is more than twice as high as that at fCD = 5% due to the finite contribution of the larger amount of uncross-linked ring molecules via combinatorial entropy in the axial polymers. The origin of the markedly small values of μ (less than 0.1) at small λ is also considered on the basis of the magnitude of the accompanying force reduction caused by the slidable function of the cross-links.

中文翻译:

螺纹环密度对带有可移动交联的聚轮烷凝胶的应变依赖性泊松比的显着影响

聚轮烷(PR)链中带环分子(f CD)的密度对应变诱导的PR凝胶溶胀具有显着影响,其中交联的环分子可沿网络链滑动。平衡泊松比(μ ),这是应变诱导体积变化的量度,对于具有在伸长率(增加了PR凝胶增加λ在中度)λ但变为恒定值(图片编号:c8sm00257f-t1.gif)在足够大的λ。当弹性模量超过阈值(ê Ç),则λ的依赖性μ 由于交联的滑动性丧失而消失。f CD分数显着影响图片编号:c8sm00257f-t2.gifE c的值。当˚F CD是足够小(<14%),图片编号:c8sm00257f-t3.gif(≈0.25)同意的值μ 为在良好溶剂中的经典凝胶。当f CD高(> 25%)时,取决于f CD和交联浓度,会以复杂的方式在图片ID:c8sm00257f-t4.gif较大范围(0.22 图片编号:c8sm00257f-t5.gif<<0.33)内变化。模量ë Ç˚F CD = 25%大于两倍高,在˚FCD = 5%,这是由于轴向聚合物中大量未交联的环分子通过组合熵的有限贡献。的显着小的值的原点μ 在小(小于0.1) λ也被认为是引起交联的可滑动功能伴随力减小的幅度的基础上。
更新日期:2018-03-22
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