Rate dependent adhesion of nanoscale polymer contacts
Rate dependent adhesion of nanoscale polymer contacts
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DOI：
10.1016/j.jmps.2021.104597
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发表时间：
2021-09-06
影响因子：
5.3
通讯作者：
Chasiotis, Ioannis
中科院分区：
文献类型：
--
作者：
Das, Debashish;Chasiotis, Ioannis
聚合物纳米纤维之间的粘附作用强烈地影响其在合成材料和生物系统中的网络的力学行为。在聚合物接触处的粘合剂相互作用的处理必须考虑接触区域中材料的粘弹性行为和相关的能量耗散。本文研究了聚丙烯腈（PAN）纳米纤维在强货车范德华力作用下的速率依赖粘附。直径为400和4000 nm的PAN纤维之间的分离力的实验测量表明，表观粘附功随卸载速率的增加而增加，卸载速率在三个数量级内增加两个因子。为了获得对这种速率依赖性粘附的进一步了解，将用于正常分离的Maugis-Dugdale（M-D）弹性接触模型扩展到包括PAN纳米纤维的线性粘弹性行为。扩展模型预测的正常拉脱力的不稳定性与实验吻合良好，捕捉以及卸载速率的影响。计算出的粘弹性时间常数为毫秒的顺序，这表明在接触区域，这解释了瞬时全强度的纳米级聚合物纤维的再附着在滑粘实验中的快速松弛。
The adhesive interactions between polymer nanofibers strongly influence the mechanical behavior of their networks in synthetic materials and biological systems. A treatment of the adhesive interactions at polymer contacts must take into account the viscoelastic behavior of the material in the contact region and the associated energy dissipation. This study focuses on the rate-dependent adhesion of polyacrylonitrile (PAN) nanofibers which interact with strong van der Waals forces. Experimental measurements of the detachment force between PAN fibers with diameters 400 and 4000 nm showed that the apparent work of adhesion increases with the rate of unloading by a factor of two within a three orders of magnitude increase in the unloading rate. In order to obtain further insights into this rate-dependent adhesion, the Maugis-Dugdale (M-D) elastic contact model for normal detachment was extended to include a linear viscoelastic behavior of the PAN nanofibers. The extended model predicted the normal pull-off force instabilities in good agreement with the experiments, capturing well the effect of the unloading rate. The calculated viscoelastic time constants were of the order of milliseconds, suggesting fast relaxations in the contact region, which explain the instantaneous full-strength reattachment of nanoscale polymer fibers during slip-stick experiments.