Pocivavsek Luka, Ye Sang-Ho, Wagner William, Tzeng Edith, Pugar Joseph, O'Dea Robert, Velankar Sachin, Cerda Enrique
Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, 15213 USA.
Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA, 15213 USA.
Nat Phys. 2018 Jul 2;14(9):948-953.
Natural surfaces excel in self-renewal and preventing bio-fouling, while synthetic materials placed in contact with complex fluids quickly foul [1, 3]. We present a novel biophysics inspired mechanism [4, 5] for surface renewal using actuating surface topography, generated by wrinkling. We calculate a critical surface curvature, given by an intrinsic characteristic length scale of the fouling layer that accounts for its effective flexural or bending stiffness and adhesion energy, beyond which surface renewal occurs. The effective bending stiffness includes the elasticity and thickness of the fouling patch, but also the boundary layer depth of the imposed wrinkled topography. The analytical scaling laws are validated using finite element simulations and physical experiments. Our data span over five orders of magnitude in critical curvatures and are well normalized by the analytically calculated scaling. Moreover, our numerics suggests an energy release mechanism whereby stored elastic energy in the fouling layer drives surface renewal. The strategy is broadly applicable to any surface with tunable topography and fouling layers with elastic response.
天然表面在自我更新和防止生物污染方面表现出色，而与复杂流体接触的合成材料很快就会被污染[1, 3]。我们提出了一种受生物物理学启发的新型机制[4, 5]，用于通过由褶皱产生的驱动表面形貌来进行表面更新。我们计算了一个临界表面曲率，它由污垢层的固有特征长度尺度给出，该尺度考虑了其有效的弯曲刚度和粘附能，超过这个临界曲率就会发生表面更新。有效的弯曲刚度包括污垢斑块的弹性和厚度，还包括施加的褶皱形貌的边界层深度。通过有限元模拟和物理实验验证了解析标度律。我们的数据涵盖了五个数量级的临界曲率，并且通过解析计算的标度很好地进行了归一化。此外，我们的数值计算表明存在一种能量释放机制，即污垢层中储存的弹性能驱动表面更新。该策略广泛适用于任何具有可调形貌的表面和具有弹性响应的污垢层。
