Reconfiguration, Welding, Reprogramming, and Complex Shape Transformation of An Optical Shape Memory Polymer Network Enabled by Patterned Secondary Crosslinking

Stimuli-triggered generation of complicated 3D shapes from 2D strips or plates without using sophisticated molds is desirable and achieving such 2D-to-3D shape transformation in combination with shape reconfiguration, welding, and reprogramming on a single material is very challenging. Here, a convenient and facile strategy using the solution of a disulfide-containing diamine for patterned secondary crosslinking of an optical shape-memory polymer network is developed to integrate the above performances. The dangling thiolectones attached to the backbones react with the diamine in the solution-deposited region so that the secondary crosslinking may not only weld individual strips into assembled 3D shapes but also suppress the relaxation of the deformed polymer chains to different extents for shape reconfiguration or heating-induced complex 3D deformations. In addition, as the dynamic disulfide bonds can be thermally activated to erase the initial programming information and the excessive thiolectones are available for subsequent patterned crosslinking, the material also allows shape reprogramming. Combining welding with patterning treatment, it is further demonstrated that a gripper can be assembled and photothermally controlled to readily grasp an object. Enabling by the reaction between thiolectones and cystamine, when deposited with the solution of cystamine in a patterning manner, the optical SMP network is made reconfigurable, weldable, reprogrammable, and transformable to complex shapes upon heating or light illumination.image

Automated summary

A convenient and facile strategy using a disulfide-containing diamine solution is developed to achieve patterned secondary crosslinking in an optical shape-memory polymer network, enabling shape reconfiguration, welding, reprogramming, and complex shape transformation. The material allows for the assembly and photothermal control of a gripper for object manipulation.