Shape Memory Polymer Microtransfer Printing Stamp with Macro-Micro Adjustable Adhesion Superhydrophobic Surface Obtained by Laser Texturing.

Abstract

The application of microtransfer technology to the manipulation process of microdevices is an area of current research. In the context of temperature-controlled microtransfer technology, the shape memory polymer (SMP) stamp plays a crucial role in microdevice manipulation, particularly surface adhesion. Aiming at the current problems such as the complexity and high cost of the SMP surface microstructure preparation process and the difficulty of surface adhesion adjustment leading to the inflexibility of microdevices pick and release, this study investigated the nanosecond ultraviolet (UV) laser ablation of superhydrophobic structures on the surface of SMP stamps and the adjustment of the surface macro-micro adhesion. The surface of the SMP stamp was ablated by laser direct writing to form a microgrid structure, which was then chemically modified to realize the superhydrophobic property of the originally hydrophilic stamp. It was found that when the surface microstructure of the SMP stamp was subjected to vertical thermal pressure, the surface microstructure of the stamp was deformed. The hydrophobicity of the whole stamp surface was weakened, and the surface adhesion was changed. Due to the shape memory property of the SMP stamp, the original microstructure state can be restored by simple heating, and the surface is still superhydrophobic after many cycles of vertical thermal pressure recovery. In this study, the superhydrophobic preparation process of the stamp surface is greatly simplified. The fine-tuning of the adhesion and wettability of the stamp surface is accomplished by changing the temperature. The macro-tuning of the stamp surface is accomplished by the regionalized design. Finally, in-plane programmable microtransfer printing was realized according to the established graphic layout of the microdevice. The macro-micro tunable adhesion superhydrophobic SMP microtransfer stamp surface has many applications in microdevice manipulation, microelectronic device assembly, and microelectromechanical system construction (MEMS).