Abstract
Polycatenane gels have attracted extensive attention due to their high
degree of freedom and mobility. However, the synthesis of
poly[2]catenane gels reported to date all rely on the polymer as the
backbone. Herein, we prepared poly[2]catenane gels based on entirely
sequential assembly of small molecules. Monomer M1 with two unclosed
rings was first prepared, which self-assembled to form supramolecular
polymers(SPs) via hydrogen bonding and π-π interactions. Upon adding
small molecule monomers M2 and M3 with aldehyde groups, ring closing of
SPs occurred due to the amino groups in the SPs reacted with M2 to form
imine bonds. In addition, M3, which has twice the number of aldehyde
groups as M2, enabled SPs to ring-close, causing the proceeding of
crosslinking process at the same time. Thus linear SPs were transformed
into poly[2]catenane gel networks. Due to the presence of hydrogen
bonds in the poly[2]catenane gel, the gel also possessed stimulus
responsiveness and self-healing properties.