Laser-Driven Shape Memory Effect for Transfer Printing Combining Parallelism with Individual Object Control

Transfer printing, a method to transfer microobjects using polymeric stamps, has been demonstrated either as a parallel process with high throughput, or as a low throughput process allowing individual manipulation of microobjects. This work presents a unique transfer printing approach which enables arbitrary pattern transfer from an array of microobjects via localized control of adhesion. This approach relies on thermally induced shape change of shape memory polymer (SMP) stamp arrays with carbon black-composite (CBSMP) microstructuring. Heat is delivered first globally by a resistive heater, facilitating parallel microobject pickup, then locally by laser illumination absorbed within the CBSMP during printing, enabling precise and selective microobject release with packing density only limited by the spot size of the accompanying laser system. The thermal response of the CBSMP system is investigated computationally using experimentally measured laser power absorption within the CBSMP system and compared with high speed photography. Several transfer printing demonstrations are provided to indicate the robust microassembly capabilities of the approach. This work provides transfer printing-based material integration with a path toward high process scalability and flexibility.