Advanced Science Research Center (ASRC), The City University of New York, 85 St. Nicholas Terrace, New York, NY, 10031, USA.
PhD Program in Physics, The Graduate Center of the City University of New York, 365 5th Ave., New York, NY, 10016, USA.
Adv Sci (Weinh). 2022 May;9(15):e2104697. doi: 10.1002/advs.202104697. Epub 2022 Mar 14.
Water-responsive (WR) materials that reversibly deform in response to humidity changes show great potential for developing muscle-like actuators for miniature and biomimetic robotics. Here, it is presented that Bacillus (B.) subtilis' peptidoglycan (PG) exhibits WR actuation energy and power densities reaching 72.6 MJ m and 9.1 MW m , respectively, orders of magnitude higher than those of frequently used actuators, such as piezoelectric actuators and dielectric elastomers. PG can deform as much as 27.2% within 110 ms, and its actuation pressure reaches ≈354.6 MPa. Surprisingly, PG exhibits an energy conversion efficiency of ≈66.8%, which can be attributed to its super-viscous nanoconfined water that efficiently translates the movement of water molecules to PG's mechanical deformation. Using PG, WR composites that can be integrated into a range of engineering structures are developed, including a robotic gripper and linear actuators, which illustrate the possibilities of using PG as building blocks for high-efficiency WR actuators.
水响应（WR）材料可响应湿度变化而可逆变形，在开发用于微型和仿生机器人的类肌肉致动器方面具有很大的潜力。本文提出，枯草芽孢杆菌（Bacillus subtilis）的肽聚糖（PG）表现出 WR 致动能量和功率密度分别达到 72.6 MJ m 和 9.1 MW m ，分别比常用致动器（如压电致动器和介电弹性体）高出几个数量级。PG 可以在 110 ms 内变形高达 27.2%，其致动压力达到约 354.6 MPa。令人惊讶的是，PG 表现出约 66.8%的能量转换效率，这归因于其超粘性纳米限制水，可有效地将水分子的运动转化为 PG 的机械变形。使用 PG 开发了可集成到各种工程结构中的 WR 复合材料，包括机器人夹具和线性致动器，这说明了将 PG 用作高效 WR 致动器构建块的可能性。
