Programmable actuation of porous poly(ionic liquid) membranes by aligned carbon nanotubes

A composite porous polymer membrane with aligned CNTs in its matrix is developed which exhibits programmable, anisotropic actuation towards organic vapors. The alignment of CNTs in multiple directions and the gradient porous structure of the membrane are critical for the actuation, and the actuating direction can be well controlled at a direction perpendicular to the longitudinal orientation of CNTs. The reversible actuation may be repeated for 300 cycles without obvious fatigue. These polymer composites are promising building blocks for a wide variety of applications such as sensors and actuators. The concept of programmable actuation succeeded here in a porous polymer mateial via complex orientation of CNTs reflects a new high level of control over physical motions that is applicable to a broad range of soft actuators.