Super Strong and Tough Polybenzimidazole/Metal Ions Coordination Networks: Reinforcing Mechanism, Recyclability, and Anti‐Counterfeiting Applications

Abstract

Nature has provided many delicate strategies for optimizing the structural characteristics of biological materials. One such strategy is the strengthening and toughening of matrix materials by aduandant and hierarchically arranged non‐covalent crosslinking. However, efficient strengthening and toughening of high‐performance aromatic polymers by non‐covalent bonds has rarely been reported yet. Herein, we report the preparation and characterizations of a metal coordination bonds crosslinked polybenzimidazole (PBI) network. By optimizing the synthetic parameters, the strength of copper ion (Cu2+) crosslinked PBI is improved from 87.8 to 218.4 MPa, and the toughness is increased from 19.4 to 111.9 MJ m−3, corresponding to increments of 148.7 % and 476.8 %, respectively, which surpass all previously reported non‐covalent bonds crosslinked high‐performance polymers. PBI with varied chain flexibility are then synthesized to deeply understand the stregnening and toughening mechanism. In addition, the glass transition temperature of PBI is dramatically increased by 75 °C after Cu2+ crosslinking. Moreover, the chemical recycling of PBI from crosslinekd network, and the development of a novel high‐temperature resistant or high‐temperature rewritable anti‐counterfeiting films based on Cu2+ crosslinked PBI are also demonstrated. This study is expected to shed light on design principle for future supramolecularly crosslinked and recyclable high‐performance polymers.

Supramolecular Polymer Networks of Ion-Coordinated Polybenzimidazole with Simultaneously Improved H2 Permeability and H2/CO2 Selectivity

“…SPNs of ion-coordinated PBI have demonstrated superior self-healing and mechanical properties. , The metal ion-based coordination is often more stable than the H-bond-based coordination due to the higher bond energy and lower sensitivities to moisture for the ion–imidazole interactions. ,, Metal ion–polymer complexes were also reported with excellent CO 2 /CH 4 separation properties due to their strong size-sieving ability. , However, to the best of our knowledge, no metal ion-induced SPNs have been reported for high-temperature H 2 /CO 2 separation.…”

Study on the Coordination Effect of Different Flexible Polybenzimidazoles with Copper Ions

“…The NMR and FTIR spectra clearly demonstrate the gradual changes in the chemical structure of copolymers. According to the optimum coordination ratios of different polybenzimidazoles and copper ions [9] , frequency and temperature sweeps were performed for the metal-organic gels formed by the coordination of five polymers and copper ions. The black and red curves in Figures 2a-e were obtained from the frequency sweep of the dynamic modulus (test temperature was 25 °C).…”

“…However, the stiffness of aromatic polymer chains can greatly affect their coordination, hindering the development of further enhancement of aromatic highperformance polymers using non-covalent bonds. Our previous work [9] reported a high-performance reversible crosslinking system based on polyether benzimidazole (OPBI) and metal ligand bonds. Due to the presence of ether groups in the main chain of OPBI, the molecular chains of the polymer are highly flexible, which allows them to be fully ligated and cross-linked with metal ions.…”

“…Rheological curves of (a) mPBI-Cu 2+ -10, (b)25% OPBI-Cu 2+ -6, (c) 50% OPBI-Cu 2+ -6, (d) 75% OPBI-Cu 2+ -4 and (e) OPBI-Cu 2+ -4. (f) Modulus versus viscosity of different polymers at 25 ºC.According to the optimum coordination ratios of different polybenzimidazoles and copper ions[9] , frequency and temperature sweeps were performed for the metal-organic gels formed by the coordination of five polymers and copper ions. The black and red curves in Figures2a-ewere obtained from the frequency sweep of the dynamic modulus (test temperature was 25 °C).…”

Metal-coordinated polybenzimidazole membranes with preferential K+ transport

“…One promising approach is introducing coordination bonds between imidazole groups with metal ions (e.g. Co 2+ , Cu 2+ , Zn 2+ ) to form coordinated networks 22 . The resulting coordinated polymer membranes exhibited higher fractional free volume and molecular sieving performance 23 .…”