固体润滑国家重点实验室（LSL）知识库

Directional transportation of objects has important applications from energy transfer, intelligent robots to biomedical devices. Although breakthroughs in liquid migration on 2D surface or 3D tubular devices have been achieved, realizing smooth/on-demand transportation of constrained solids within 3D cavity environment under harsh pressurized environment still remains a daunting challenge, where strong interface friction force becomes the main obstacle restricting the movement of solids. Inspired by typical feeding mechanism in natural esophagus system which synergistically couples a lubricating mucosa surface with the peristaltic contraction deformation of cavity, herein we address this challenge by constructing an esophagus-inspired layered tubular actuator with slippery inner surface and responsive hydrogel matrix to realize spherical solid propulsion by photo(thermo)-induced cavity deformation. The as-constructed tubular actuator containing Fe₃O₄ nanoparticles exhibits local volumetric shrinkage upon NIR-irradiation, which can generate large hydrodynamic pressure and considerable mechanical extrusion force (F_{driving force}~0.18 N) to overcome low interface friction force (f_{friction force}~0.03 N), enabling on-demand transportation of constrained (pressure: 0.103 MPa) spherical solids over a long distance along arbitrary direction. This actuator is anticipated to be used as bionic medicine transportation devices or artificial in vitro esophagus simulation systems, for example, to help formula eating-related physiotherapy plans for patients and astronauts.