An Underwater Long‐Term Strong Adhesive Based on Boronic Esters with Enhanced Hydrolytic Stability

Abstract

Boron‐based adhesives have attracted considerable attention in recent years due to their strong adhesive behavior and reversible capacities. However, limited by the humidity sensitivity and poor dynamicity, it remains challenging for the boron‐based adhesive materials to realize strong and long‐term adhesion underwater. In this study, a novel boronic ester (BN‐6) with changeable ring strain induced by the heat‐responsive BN coordination bond is designed and synthesized. Due to the low strain of the six‐membered ring at ambient conditions and the high strain of the ten‐membered ring at elevated temperature, BN‐6 exhibits enhanced hydrolytic/thermal stabilities as well as dynamicity. The model dynamic crosslinking polymers containing BN‐6 linkages present significantly improved water‐resistance and recyclability. Specifically, based on the hydrolytically stable whilst kinetically active boronic ester linkage, a strong and recyclable adhesive material is successfully prepared. Long‐term adhesion performance under water and harsh conditions is realized on different substrates, with the maximum adhesion strength of 4.21 MPa. The report provides a novel chemical strategy for designing stable and dynamic boronic ester linkages and the synthesized adhesive has pioneered in the field of long‐term underwater application of boron‐based adhesives.

Fully recyclable multifunctional adhesive with high durability, transparency, flame retardancy, and harsh-environment resistance

“…Following the procedure in Fig. 2A , the adhesion performances between various separated substrates bonded by the P(DPOP-Si) adhesive were monitored in detail ( 40 ). Note that the adhesive with a small contact area (about 2 cm × 1 cm) on the smooth glass substrate could hold a 1-kg weight easily ( Fig.…”

Highly stretchable and stretch-induced fluorescence chromism self-healing materials based on boroxine and dynamic imine bond

“…Previous studies have proved that the N atom can coordinate with the B atom of boroxine, and internal and external coordination bonds can form. 51,52 B-N internal coordination bond can enhance the boroxine bond, while the B-N external coordination bond can weaken the boroxine bond. Therefore, the B-N internal coordination bond can enhance the hydrolytic stability of boroxine.…”

“…Therefore, the B–N internal coordination bond can enhance the hydrolytic stability of boroxine. 52 For PDMS-DPBA-5000, the position of the N atom makes the B–N internal coordination bond not to form. In addition, from the 11 B NMR spectrum (Fig.…”

N-Coordinated Organoboron in Polymer Synthesis and Material Science

“…Liu et al further revealed the effect of the ring size of N-coordinated boronate ester on the properties of the materials by tuning the structure of tridentate ligands . A six-membered, N-coordinated boronate ester (BN-6) was prepared and applied in a polymeric adhesive (Figure a).…”

“…(a) Synthesis route of hermosets based on six-membered N-coordinated boronic ester (TBN6) and schematic illustration of multiple dynamic bonds in the polymer network. (b) The variable temperature 11 B NMR spectra and dynamic configuration transformation of boronic esters BN-6 (top) and BN-5 (below) during heating (500 MHz, DMSO- d 6 ) . Panels (a,b) were reproduced with permission from ref .…”