Porous Membrane‐Enabled Fast Liquid Metal Patterning in Thin Blind‐Ended Microchannels

Abstract A porous membrane‐enabled fast liquid metal patterning method in thin blind‐ended microchannels is reported. The principle is to introduce a thin porous membrane in polydimethylsiloxane (PDMS) chips, effectively releasing the air pressure of the inner microchannel during the injection process. Traditional direct injection method requires microchannels with both an inlet and an outlet, making blind‐ended microchannel filling impossible. The vacuum filling requires adequate chip thickness and stiffness for the channel to recover after filling. Additionally, high injection pressure may cause leakages and damage to the microchannels. Experiment results indicate that this novel method promotes the injection in thin blind‐ended microchannels without voids and damages. The finest channel that can be filled successfully using this mechanism is with around 12 µm width and 20 µm height. Series of tensile texts for comb capacitor demonstrate that the electrodes have marvelous flexibility. Overall, the capability of filling the mazy blind‐ended channels entirely quickly makes it promising in the fast fabrication of ultrathin stretchable electronics.