Wu Min, Chen Song, Mei Yang, Liu Lan, Wei Yong
School of Materials and Chemistry, Engineering Research Center of Biomass Materials, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, P. R. China.
College of Materials Science and Engineering, Key Lab of Guangdong Province for High Property and Functional Macromolecular Materials, South China University of Technology, Guangzhou 510641, P. R. China.
ACS Appl Mater Interfaces. 2022 Sep 14;14(36):41456-41467. doi: 10.1021/acsami.2c12553. Epub 2022 Aug 30.
Detachable adhesives with simultaneously high bonding strength and detaching efficiency have remained a great challenge in adhesion science. The existing detachable adhesives (e.g., solid-liquid phase transitions-based adhesives) usually show low initial cohesion and require long detaching time (several minutes or hours for transitions). Herein, by introducing ionic liquids (ILs) and soft polyethylene glycol (PEG) into a rigid epoxy precursor and curing, we demonstrated the adhesives with both high initial bonding strength (>13 MPa) and detaching efficiency (100% detachment within 10 s under a 90 V DC voltage). The high initial bonding strength is due to the imidazolium cations of ILs and their ion-dipole interactions with PEG can promote the curing of epoxy, decrease the glass-transition temperature, increase the interfacial wettability, and transmit external stress. Also, the outstanding detaching efficiency is because the tetrafluoroborate anions of ILs can electrochemically react rapidly under a voltage and generate fluorinated nanoparticles at the bonding interface within 1 minute. The high bonding and electrochemistry-induced detaching mechanism were further characterized. This work opens up a new avenue for the rational design of fast-detachable adhesives with high bonding strength, showing wide potential in many modern fields.
同时具备高粘结强度和剥离效率的可分离粘合剂在粘附科学领域一直是一项巨大挑战。现有的可分离粘合剂（例如基于固-液相转变的粘合剂）通常初始内聚力较低，且需要较长的剥离时间（转变过程需要几分钟或几小时）。在此，通过将离子液体（ILs）和柔软的聚乙二醇（PEG）引入刚性环氧前驱体并进行固化，我们展示了一种兼具高初始粘结强度（>13 MPa）和剥离效率（在90 V直流电压下10秒内100%分离）的粘合剂。高初始粘结强度归因于离子液体的咪唑阳离子，其与PEG的离子-偶极相互作用可促进环氧固化、降低玻璃化转变温度、提高界面润湿性并传递外部应力。此外，出色的剥离效率是因为离子液体的四氟硼酸根阴离子在电压作用下能快速发生电化学反应，并在1分钟内在粘结界面生成氟化纳米颗粒。对高粘结和电化学诱导的分离机制进行了进一步表征。这项工作为合理设计具有高粘结强度的快速可分离粘合剂开辟了一条新途径，在许多现代领域显示出广阔的潜力。
