A thermal actuated switchable dry adhesive with high reversibility for transfer printing

Abstract

Transfer printing based on switchable adhesive that heterogeneously integrates materials is essential to develop novel electronic systems, such as flexible electronics and micro LED displays. Here, we report a robust design of a thermal actuated switchable dry adhesive, which features a stiff sphere embedded in a thermally responsive shape memory polymer (SMP) substrate and encapsulated by an elastomeric membrane. This construct bypasses the unfavorable micro- and nano-fabrication processes and yields an adhesion switchability of over 1000 by combining the peel-rate dependent effect of the elastomeric membrane and the thermal actuation of the sub-surface embedded stiff sphere. Experimental and numerical studies reveal the underlying thermal actuated mechanism and provide insights into the design and operation of the switchable adhesive. Demonstrations of this concept in stamps for transfer printing of fragile objects, such as silicon wafers, silicon chips, and inorganic micro-LED chips, onto challenging non-adhesive surfaces illustrate its potential in heterogeneous material integration applications, such as flexible electronics manufacturing and deterministic assembly.

Emerging Optoelectronic Devices Based on Microscale LEDs and Their Use as Implantable Biomedical Applications

“…Thanks to the high spatial resolution and patterned shape features of the laser, the high selectivity and multi-device transfer printing process can be realized. In addition to the PDMS stamp, the tapes with adjustable adhesives are also a good choice for transfer printing, such as soluble tape (ST) [ 63 , 64 , 65 , 66 ], thermal release tape (TRT) [ 67 , 68 , 69 , 75 ], and ultraviolet (UV) tape [ 70 , 71 ]. Figure 1 f illustrates the tape transfer printing operation procedure schematically with acetone used as a binder conditioner [ 65 ].…”

Dry‐Transferable Photoresist Enabled Reliable Conformal Patterning for Ultrathin Flexible Electronics

“…In addition, dry transfer printing is compatible with a wide range of substrates, making it an ideal technique for fabricating wearable electronics and other flexible electronic devices. Several advanced dry transfer printing techniques, including kinetics-controlled transfer printing, [27,28] laser irradiation-based, [29][30][31] temperature-controlled, [32][33][34] and magnetic-assisted techniques, [35] have been developed to integrate micro/nanoscale flexible devices onto target substrates. Dry transfer printing techniques can also be integrated with multiscale patterning techniques and post-mechanical assembly processes to enable the manufacturing of conformal devices on various complex surfaces.…”

Aphid‐Inspired and Thermally‐Actuated Soft Gripper Using 3D Printing Technology

“…[18,19] To overcome this challenge, many researchers have developed soft gripper systems with various dry adhesives inspired by nature, such as geckos [20][21][22][23][24][25] and aphids. [26][27][28][29][30] Among biomimetic adhesives, geckoinspired adhesives have attracted much interest because of their strong adhesion and easy detachment. [31][32][33] Gecko-inspired adhesives often mimic the micro-or nanofibrillar structures on the feet of a gecko, which enable adhesion.…”

“…To resolve this manufacturing complexity, researchers have extensively investigated aphid-inspired adhesives because they have a simple structure and mechanism for converting adhesion states, thus not requiring complex fabrication processes. [26,27] These studies have successfully developed high adhesion strengths, reversible adhesion states, and repeatable adhesives using simple fabrication processes, such as preparing a mold, curing the elastomers, and sealing the actuation parts. Although this bypasses the complex fabrication method (lithography and etching), previous studies have involved several fabrication processes, including mold manufacturing, casting, and sealing the actuation part to create a smart dry adhesive.…”