Lang Michael, Scholz Reinhard
Leibniz Institute of Polymer Research Dresden, Hohe Straße 6, 01069, Dresden, Germany.
Macromol Rapid Commun. 2024 May;45(10):e2400025. doi: 10.1002/marc.202400025. Epub 2024 Feb 22.
Large scale computer simulations are employed to analyze the conformations of network strands in polymer networks at preparation conditions (characterized by a polymer volume fraction of ϕ) and when swollen to equilibrium (characterized by a polymer volume fraction ϕ < ϕ). Network strands in end-linked model networks are weakly stretched and partially swollen at preparation conditions as compared to linear polymers in the same solvent at ϕ. Equilibrium swelling causes non-ideal chain conformations characterized by an effective scaling exponent approaching 7/10 on intermediate length scales for increasing overlap of the chains. The chain size in a network consists of a fluctuating and a time average "elastic" contribution. The elastic contribution swells essentially affinely ∝(ϕ/ϕ), whereas the swelling of the fluctuating part lies between the expected swelling of the entanglement constraints and the swelling of non-cross-linked chains in a comparable semi-dilute solution. The total swelling of chain size results from the changes of both fluctuating and non-fluctuating contributions.
大规模计算机模拟用于分析聚合物网络在制备条件下（以聚合物体积分数ϕ表征）以及溶胀至平衡时（以聚合物体积分数ϕ<ϕ表征）网络链的构象。与相同溶剂中处于ϕ的线性聚合物相比，端基交联模型网络中的网络链在制备条件下受到弱拉伸且部分溶胀。平衡溶胀导致非理想的链构象，其特征在于，在中间长度尺度上，随着链重叠的增加，有效标度指数接近7/10。网络中的链尺寸由波动部分和时间平均“弹性”部分组成。弹性部分基本上以仿射方式溶胀∝(ϕ/ϕ)，而波动部分的溶胀介于缠结约束的预期溶胀和可比半稀溶液中未交联链的溶胀之间。链尺寸的总溶胀是由波动部分和非波动部分的变化共同导致的。
