Thermal/Light Dual-Activated Shape Memory Hydrogels Composed of an Agarose/Poly(acrylamide-co-acrylic acid) Interpenetrating Network

Abstract

In this work, an agarose/poly(acrylamide‐co‐acrylic acid) interpenetrating network hydrogel is prepared by the photopolymerization of acrylamide, acrylic acid, and N,N′‐methylenebisacrylamide within agarose network at its gel state. The as‐prepared hydrogel exhibits two independent kinds of shape memory effects. The thermal‐activated shape memory behavior is attributed to the reversible coil‐helix transformation of agarose, within the permanently cross‐linked poly(acrylamide‐co‐acrylic acid) network; the light triggered shape recovery is driven by the dissociation of the complexes between carboxyl groups and Fe(III) ions, due to the photoreduction of Fe(III) to Fe(II) in the presence of citric acid. The versatile and simple strategy as presented here should be beneficial for the design of dual‐activated shape memory hydrogels and foster their use in a number of fields such as biomaterials, soft robotics, smart actuators, and sensors.

Rigid and Strong Thermoresponsive Shape Memory Hydrogels Transformed from Poly(vinylpyrrolidone-co-acryloxy acetophenone) Organogels

“…SMHs are mainly prepared by utilizing reversible interactions, such as hydrophobic interaction, 18,19 ionic interaction, 20,21 host−guest inclusion, 22,23 hydrogen bonding, 24−26 dynamic covalent bond, 27 and coil−helix transformation. 28 Osada and co-workers 18,29 first reported the shape memory effect in hydrogels prepared by radical copolymerization of stearyl acrylate (C18) and acrylic acid (AA). The reversible order−disorder transition, i.e., the crystallization and melting of crystalline regions, associated with the hydrophobic interaction between C18 side chains endows the hydrogels with excellent shape memory properties.…”

“…SMHs are mainly prepared by utilizing reversible interactions, such as hydrophobic interaction, , ionic interaction, , host–guest inclusion, , hydrogen bonding, − dynamic covalent bond, and coil–helix transformation . Osada and co-workers , first reported the shape memory effect in hydrogels prepared by radical copolymerization of stearyl acrylate (C18) and acrylic acid (AA).…”

Double network hydrogels with controlled shape deformation: A mini review

“…The network structure of DN gel at each state could be found in Figure (bv). Yang et al also reported a novel thermal/light responsive agarose/poly(acrylamide‐ co ‐acrylic acid) (agarose/poly(AM‐ co ‐AAc) DN gels with controlled shape deformation. Similarly, the thermal‐activated shape deformation was controlled by the reversible sol–gel transition of agarose in the first network, while the chemically crosslinked poly(AM‐ co ‐AAc) second network served as the permanent shape [Fig.…”

Stretchable Semi-Interpenetrating Carboxymethyl Guar Gum-Based Composite Hydrogel for Moisture-Proof Wearable Strain Sensor

“…At present, polysaccharide polymers (chitosan, , agarose, − lignin, , cellulose, ,, and guar gum , ) provide an alternative route to construct functional hydrogels for their biocompatibility, nontoxicity, low cost, and environmental friendliness. However, their applications are limited due to the monotonous function and poor mechanical properties.…”