Bacca Mattia, Saleh Omar A, McMeeking Robert M
Mechanical Engineering Department, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Soft Matter. 2019 Jun 5;15(22):4467-4475. doi: 10.1039/c8sm02598c.
We propose a theory based on non-equilibrium thermodynamics to describe the mechanical behavior of an active polymer gel created by the inclusion of molecular motors in its solvent. When activated, these motors attach to the chains of the polymer network and shorten them creating a global contraction of the gel, which mimics the active behavior of a cytoskeleton. The power generated by these motors is obtained by an ATP hydrolysis reaction, which transduces chemical energy into mechanical work. The latter is described by an increment of strain energy in the gel due to an increased stiffness. This effect is described with an increment of the cross-link density in the polymer network, which reduces its entropy. The theory then considers polymer network swelling and species diffusion to describe the transient passive behavior of the gel. We finally formulate the problem of uniaxial contraction of a slab of gel and compare the results with experiments, showing good agreement.
我们提出一种基于非平衡热力学的理论，以描述通过在溶剂中加入分子马达而形成的活性聚合物凝胶的力学行为。当被激活时，这些马达附着在聚合物网络的链上并使其缩短，从而使凝胶整体收缩，这模拟了细胞骨架的活性行为。这些马达产生的动力通过ATP水解反应获得，该反应将化学能转化为机械功。后者通过凝胶中应变能的增加来描述，这是由于刚度增加所致。这种效应通过聚合物网络中交联密度的增加来描述，这降低了其熵。该理论随后考虑聚合物网络的溶胀和物种扩散，以描述凝胶的瞬态被动行为。我们最终阐述了凝胶平板单轴收缩的问题，并将结果与实验进行比较，结果显示吻合良好。
