Macromolecular Rapid Communications

Reversible light-control over molecular mechanical properties has attracted great recent interest for the development of polymeric optical-to-mechanical actuators. In this review, recent examples and emerging trends in this exciting field of research are highlighted, covering a wide range of polymers containing azobenzene photo-reversible switches, and their demonstration as functional ‘artificial muscles’, ‘devices’, and simple ‘molecular robotic machines’.

Tunable non-linear resistivity followed by saturation was demonstrated for polymer-grafted and silanized rGO in EBA-matrix for the first time. The nonlinearity and onset were tuned by the length of polymer-grafts, which provided controlled inter-flake distances. The surface modifications stabilized the rGO thermally and the rGO-composites are therefore interesting as field-grading materials in compact HVDC cable accessories (cable terminations and joints).

The design of multiurea linkage segmented linear copolymers with tractable synthesis, processability, hybridization, and recyclability is reported in this work, having accessible handles with which fully swollen ultrastrong hydrogels or stretchable hydrogel fibers with nano-, micro-, or macroscale diameters can be produced via different manufacturing techniques including compression, solution casting, or spinning.

Nanoclusters and self-assembled reduction-responsive sub-5-nm discrete subdomains are achieved via coordination-driven self-assembly of 9% imidazole motifs in hydrophilic copolymer in the presence of Cu(II) in water; metal-center reduction using sodium ascorbate induces superstructure rearrangement one-order backwards.

A novel dihydroxyl-functionalized triptycene diamine, 2,6(7)-dihydroxy-3,7(6)-diaminotriptycene (DAT1-OH), was designed and used for the synthesis of an intrinsically microporous polyimide, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride-DAT1-OH. The solution-processable polyimide is plasticization resistant and exhibits excellent mixed-gas performance with CO₂ permeability of 50 Barrer and CO₂/CH₄ selectivity of 40 at a typical natural gas wellhead pressure of 10 bar.