Lee Tae-Hyung, Han Gi-Yeon, Yi Mo-Beom, Kim Hyun-Joong, Lee Jae-Hak, Kim Seungman
Program in Environmental Materials Science, Department of Agriculture, Forestry, and Bioresources, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
Research Institute of Agriculture and Life Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
ACS Appl Mater Interfaces. 2021 Sep 15;13(36):43364-43373. doi: 10.1021/acsami.1c11680. Epub 2021 Sep 1.
Materials that can switch adhesive properties based on external stimuli are required in several industries for temporary bonding or transfer processes. Previously studied materials achieve this under restricted conditions (hydration, heat, and long switching times), and some materials have limitations related to reuse because of irreversible reactions or residue formation on substrates. Herein, a rapid photoresponsive switchable pressure-sensitive adhesive (PSA) fabricated using an acrylic polymer and an aliphatic monomer containing azobenzene is reported. The adhesion force of the proposed PSA can be switched by photoisomerizing the azobenzene moiety. The process induces the transition of surface energy and modulus of the PSA. Ultraviolet and visible light irradiation can switch the probe tack force from 200 to 4 kPa within 15-30 s. Adhesion switching is possible in a state wherein the PSA remains adhered to a substrate. Mini-LEDs are selectively transferred from the carrier PSA to a polydimethylsiloxane substrate following the process of partial adhesion switching of the PSA. The novel and switchable PSA, which exhibits a selective and repeatable adhesion switching property and high switching ratio when stimulated by light stimuli, may be potentially used to realize the mini-LED or micro-LED transfer processes.
在多个行业的临时粘合或转移工艺中，需要能够根据外部刺激切换粘合特性的材料。先前研究的材料在受限条件下（水合、加热和较长的切换时间）才能实现这一点，并且一些材料由于不可逆反应或在基材上形成残留物而存在与再利用相关的局限性。在此，报道了一种使用丙烯酸聚合物和含偶氮苯的脂肪族单体制造的快速光响应可切换压敏粘合剂（PSA）。所提出的PSA的粘附力可通过使偶氮苯部分进行光异构化来切换。该过程会引起PSA表面能和模量的转变。紫外线和可见光照射可在15 - 30秒内将探针粘性力从200 kPa切换至4 kPa。在PSA仍粘附于基材的状态下，粘附切换是可行的。按照PSA的部分粘附切换过程，微型发光二极管（Mini - LED）从载体PSA选择性地转移至聚二甲基硅氧烷基材上。这种新型的可切换PSA在受到光刺激时表现出选择性和可重复的粘附切换特性以及高切换率，可能潜在地用于实现Mini - LED或微型发光二极管（micro - LED）的转移工艺。
