Chemical and Photochemical-Driven Dissipative Fe(3+)/Fe(2+)-Ion Cross-Linked Carboxymethyl Cellulose Gels Operating Under Aerobic Conditions: Applications for Transient Controlled Release and Mechanical Actuation

A Fe(3+)-ion cross-linked carboxymethyl cellulose, Fe(3+)-CMC, redox-active gel exhibiting dissipative, transient stiffness properties is introduced. Chemical or photosensitized reduction of the higher-stiffness Fe(3+)-CMC to the lower-stiffness Fe(2+)-CMC gel, accompanied by the aerobic reoxidation of the Fe(2+)-CMC matrix, leads to the dissipative, transient stiffness, functional matrix. The light-induced, temporal, transient release of a load (Texas red dextran) and the light-triggered, transient mechanical bending of a poly-N-isopropylacrylamide (p-NIPAM)/Fe(3+)-CMC bilayer construct are introduced, thus demonstrating the potential use of the dissipative Fe(3+)-CMC gel for controlled drug release or soft robotic applications.