An ion-terminated hyperbranched polymer towards multipurpose adhesive with record-high bonding strength and sensitive stress-sensing

Abstract

The inherent contradiction between pressure-sensitive adhesives (PSAs) and hot-melt adhesives (HMAs) originating from different molecular mechanisms remains a considerable challenge to develop high-performance, multipurpose, and stress-sensing adhesives despite being vital in engineering monitoring, intelligent sensing, anti-counterfeiting, etc. Herein, an ion-terminated hyperbranched polymer is constructed to overcome the intrinsic contradiction between PSA and HMA and enable it to be a multipurpose one. The electrostatic interaction and hydrogen bond networks formed between the inter/intramolecular motifs result in excellent bonding strength for both PSA (2.85 MPa) and HMA (7.67 MPa) just under gentle pressing. To the best of our knowledge, it is the record-high value among the reported PSA. Interestingly, it can be further enhanced to 3.67 MPa once an electric field is applied due to the orientation or migration of ionic groups. The excellent stress-sensing capability with a sensitivity of 118.8 MPa⁻¹ (PSA) and 164.6 MPa⁻¹ (HMA) endows it with fast response to the external stress and rapid transmission of encrypted signals. Moreover, multi-functionalities, such as remarkable fluorescence as a result of aggregation-induced emission, good water-proof characteristics due to the hydrophobic ionic groups, rapid self-healing performance via fast relaxation, and reversible dynamics of hydrogen bond as well as electrostatic interaction, are also achieved.