Mechanistic insights of evaporation-induced actuation in supramolecular crystals
Mechanistic insights of evaporation-induced actuation in supramolecular crystals
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DOI：
10.1038/s41563-020-0799-0
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发表时间：
2020-09-14
期刊：
影响因子：
41.2
通讯作者：
Chen, Xi
中科院分区：
文献类型：
--
作者：
Piotrowska, Roxana;Hesketh, Travis;Chen, Xi
实验和分子动力学模拟表明，脱水诱导的纳米多孔三肽晶体的致动是由于孔内水氢键网络的加强引起的孔收缩，这产生了使晶格变形的机械应力。水响应材料在不同的湿度水平下发生可逆的形状变化。这些机械上坚固而灵活的结构可以施加相当大的力，并有望成为能量收集，自适应材料和软机器人的高效致动器。在这里，我们证明了蒸发诱导的驱动纳米多孔三肽晶体的过程中的能量转移的结果从水氢键的加强，驱动孔的收缩。这些孔内的移动的和结构上结合的水与包含容易变形的芳族结构域的超分子网络的无缝整合通过晶格翻译脱水诱导的机械应力，表明有效的水响应性致动的一般机制。所观察到的水结合的加强补充了对这类材料的毛细力引起的可逆收缩的公认理解。与天然水响应材料相比，这些极简的肽晶体的组成要简单得多，这里提供的见解可以更广泛地应用于高能分子致动器的设计。
Experiments and molecular dynamics simulations show that the dehydration-induced actuation of nanoporous tripeptide crystals is a result of pore contraction caused by the strengthening of the water hydrogen-bonding network inside the pore, which creates mechanical stress that deforms the crystal lattice.Water-responsive materials undergo reversible shape changes upon varying humidity levels. These mechanically robust yet flexible structures can exert substantial forces and hold promise as efficient actuators for energy harvesting, adaptive materials and soft robotics. Here we demonstrate that energy transfer during evaporation-induced actuation of nanoporous tripeptide crystals results from the strengthening of water hydrogen bonding that drives the contraction of the pores. The seamless integration of mobile and structurally bound water inside these pores with a supramolecular network that contains readily deformable aromatic domains translates dehydration-induced mechanical stresses through the crystal lattice, suggesting a general mechanism of efficient water-responsive actuation. The observed strengthening of water bonding complements the accepted understanding of capillary-force-induced reversible contraction for this class of materials. These minimalistic peptide crystals are much simpler in composition compared to natural water-responsive materials, and the insights provided here can be applied more generally for the design of high-energy molecular actuators.