Capadona Jeffrey R, Shanmuganathan Kadhiravan, Tyler Dustin J, Rowan Stuart J, Weder Christoph
Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
Science. 2008 Mar 7;319(5868):1370-4. doi: 10.1126/science.1153307.
Sea cucumbers, like other echinoderms, have the ability to rapidly and reversibly alter the stiffness of their inner dermis. It has been proposed that the modulus of this tissue is controlled by regulating the interactions among collagen fibrils, which reinforce a low-modulus matrix. We report on a family of polymer nanocomposites, which mimic this architecture and display similar chemoresponsive mechanic adaptability. Materials based on a rubbery host polymer and rigid cellulose nanofibers exhibit a reversible reduction by a factor of 40 of the tensile modulus, for example, from 800 to 20 megapascals (MPa), upon exposure to a chemical regulator that mediates nanofiber interactions. Using a host polymer with a thermal transition in the regime of interest, we demonstrated even larger modulus changes (4200 to 1.6 MPa) upon exposure to emulated physiological conditions.
海参和其他棘皮动物一样，能够快速且可逆地改变其内部真皮层的硬度。有人提出，这种组织的模量是通过调节胶原纤维之间的相互作用来控制的，这些胶原纤维增强了低模量基质。我们报道了一类聚合物纳米复合材料，它们模仿这种结构，并表现出类似的化学响应机械适应性。例如，基于橡胶状主体聚合物和刚性纤维素纳米纤维的材料，在暴露于介导纳米纤维相互作用的化学调节剂时，拉伸模量会可逆地降低40倍，从800兆帕降至20兆帕（MPa）。使用在感兴趣的温度范围内具有热转变的主体聚合物，我们证明在模拟生理条件下模量变化更大（从4200兆帕降至1.6兆帕）。
