Multiple host-guest and metal coordination interactions induce supramolecular assembly and structural transition

Three monomers, namely A2, B2, and GH, were designed and synthesized. By utilizing double host-guest interactions, the monomers A2+B2+GH underwent self-assembly to form a supramolecular linear polymer (SLP) at high concentrations. Long fibers could be pulled from the concentrated SLP solution. Upon the addition of PdCl₂(PhCN)₂ into the SLP solution, a structural transformation occurred from SLP to a supramolecular crosslinked polymer (SCP) through metal coordination interaction. This transformation induced fluorescence quenching, test paper strips for ion detection experiment confirmed that the SLP had good detection ability for Pd²⁺. Furthermore, the SCP underwent a transformation into a gel when the concentration exceeded 145 mmol/L. The SCP gel demonstrated sensitivity to different stimuli, such as K⁺ ions and changes in temperature, accompanied by a reversible transition between sol and gel states. Additionally, rheological analyses indicated that the gel possessed favorable self-healing properties.