Direct Laser Writing-Based Programmable Transfer Printing via Bioinspired Shape Memory Reversible Adhesive

Abstract

Flexible and stretchable electronics offer a wide range of unprecedented opportunities beyond conventional rigid electronics. Despite their vast promise, a significant bottleneck lies in the availability of a transfer printing technique to manufacture such devices in a highly controllable and scalable manner. Current technologies usually rely on manual stick-and-place and do not offer feasible mechanisms for precise and quantitative process control, especially when scalability is taken into account. Here, we demonstrate a spatioselective and programmable transfer strategy to print electronic microelements onto a soft substrate. The method takes advantage of automated direct laser writing to trigger localized heating of a micropatterned shape memory polymer adhesive stamp, allowing highly controlled and spatioselective switching of the interfacial adhesion. This, coupled to the proper tuning of the stamp properties, enables printing with perfect yield. The wide range adhesion switchability further allows printing of hybrid electronic elements, which is otherwise challenging given the complex interfacial manipulation involved. Our temperature-controlled transfer printing technique shows its critical importance and obvious advantages in the potential scale-up of device manufacturing. Our strategy opens a route to manufacturing flexible electronics with exceptional versatility and potential scalability.

Laser Transfer, Printing, and Assembly Techniques for Flexible Electronics

“…Inset figures in Figure a exhibit representative adhesion‐on and adhesion‐off states of the stamp with different ink‐stamp interfacial contact areas. The use of common micropatterned SMP stamp still relies on laser‐absorbing ink material . An improved approach is using composite carbon black‐SMP (CBSMP).…”

“…f) Comparison of interfaces and growth substrates for Si and GaAs and the intended hybrid printing layout. Reproduced with permission . Copyright 2016, American Chemical Society.…”

“…These materials are prevented to use in LMTP approaches. Besides, this technique can further allow the hybrid printing of Si and GaAs from different substrates (Figure f) . The significant difference in interfacial adhesion due to their disparate deposition methods, interfacial layers, and growth substrates, as well as their intrinsic fragility, make the hybrid printing particularly challenging.…”

Reversible Underwater Dry Adhesion of a Shape Memory Polymer

“…Here, we introduce a reversible underwater yet dry adhesive that relies on van der Waals forces by combining the pressure‐driven squeeze‐out of liquid at a soft interface and the shape memory effect of a shape memory polymer (SMP). An SMP is a class of external‐stimuli responsive polymer with the ability to memorize its “permanent shape” which is recoverable from a deformed shape, i.e., “temporary shape.” In particular, a thermoresponsive SMP undergoes a dramatic change in storage modulus across the glass transition temperature ( T g ) between glassy and rubbery states, and generally shows a strong shape memory effect, i.e., ability to stably fix its temporary shape and fully recover its permanent shape . As suggested elsewhere, the adhesion strength ( F ) of a reversible dry adhesive is inversely proportional to the square root of the adhesive system compliance ( C ) as below when material properties and true contact area ( A ) associated with the adhesive‐adherend interface are fixed…”

A Facile Fabrication of PCL/OBC/MWCNTs Nanocomposite with Selective Dispersion of MWCNTs to Access Electrically Responsive Shape Memory Effect

“…However, there still exist some defects such as inconvenience of direct heating, lacking performances and poor mechanical properties. In order to solve these problems and expand the application of SMPs, much attention has been paid to develop novel SMPs triggered by stimuli other than heat recently [6,13,[28][29][30][31][32][33][34]. To this end, metal and carbon-based materials are usually added as the conductive filler preparing electrically actuated SMPs [7][8][9][10].…”