Kinetic trapping of 3D-printable cyclodextrin-based poly(pseudo)rotaxane networks

Synthetically trapping kinetically varied (super)structures of molecular assemblies and amplifying them to the macroscale is a promising, yet challenging, approach for the advancement of meta-stable materials. Here, we demonstrated a concerted kinetic trapping design to timely resolve a set of transient polypseudorotaxanes in solution and harness a crop of them via micro-crystallization. By installing stopper or speed bump moieties on the polymer axles, meta-stable polypseudorotaxanes with segmented cyclodextrin blocks were hierarchically amplified into crystalline networks of different crosslinking densities at mesoscale and viscoelastic hydrogels with 3D-printability in bulk. We demonstrated simultaneous 3D-printing of two polypseudorotaxane networks from one reactive ensemble and their conversion to heterogeneous polyrotaxane monoliths. Spatially programming the macroscale shapes of these heterogeneous polyrotaxanes enabled the construction of moisture-responsive actuators, in which the shape morphing originated from the different numbers of cyclodextrins interlocked in these polyrotaxane networks.

Automated summary

The study demonstrates a method for controlling molecular assembly structures through kinetic trapping design and amplifying them to the macroscale, achieving the capturing of transient polypseudorotaxanes from solution and obtaining materials with different physical properties. By 3D printing different shapes of polypseudorotaxane networks, moisture-responsive actuators can be constructed.