Construction of self-healing multifunctional hyper-crosslinked hyperbranched polymer @ metal–organic polyhedra (HHMOP) membranes

Abstract

The preparation of hybrid membranes composed of polymer matrix and porous materials is a hot topic. Herein, a highly reversible hyper-crosslinked hyperbranched polymer @ metal–organic polyhedra (HHMOP) membrane was designed and synthesized using hyperbranched polyamide amine (HPMA), UiO-66-NH2, diethylenetriamine, and terephthalaldehyde through a multi-component Schiff-base condensation reaction of aldehyde and amine groups. The structures of HHMOP membranes were characterized by FTIR, XRD, and SEM. The mechanical properties, thermal properties, reversible self-healing properties, and biological activity of the membranes were studied. Introducing HPMA as hyper-crosslinking monomer and UiO-66-NH2 as porous comonomers into the network resulted in HHMOPs membranes with multiple functionalities: flexibility, humidity sensitivity, self-healing capacity, antibacterial capacity and better mechanical properties than the original polyimine films. The tensional intensity and breaking elongation of HHMOP membrane has been remarkably ameliorated, with the maximum tensile strength reached 54.64 MPa. The membranes showed humidity-sensitive mechanical properties and excellent self-healing performance, with 91.35 % strength revovered after 24-hours at room temperature and a relative humidity of 60 %, indicating that HPMA has a significant impact on the humidity responsiveness and self-healing performance of HHMOP membranes. The HHMOP membrane also demonstrated good antibacterial activity against common food lethal bacteria like the gram-positive Staphylococcus aureus and gram-negative Escherichia coli. This work will greatly enrich the devise and preparation of versatile membranes and broaden the use of MOFs.