Jammed Microgel‐Based Inks for 3D Printing of Complex Structures Transformable via pH/Temperature Variations. Issue 19 (23rd June 2022)

• Record Type: Journal Article
• Authors: Moon, Dowon; Lee, Min‐Gyu; Sun, Jeong‐Yun; Song, Kwang Hoon; Doh, Junsang
• Is Part Of: Macromolecular rapid communications. Volume 43:Issue 19(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-23
• Subjects: 3D printing -- jamming -- microgel -- stimuli‐responsive hydrogel; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.202200271
• Languages: English
• ISSNs: 1022-1336

Abstract

Abstract: Structure changes mediated by anisotropic volume changes of stimuli‐responsive hydrogels are useful for many research fields, yet relatively simple structured objects are mostly used due to limitation in fabrication methods. To fabricate complex 3 dimensional (3D) structures that undergo structure changes in response to external stimuli, jammed microgel‐based inks containing precursors of stimuli‐responsive hydrogels are developed for extrusion‐based 3D printing. Specifically, the jammed microgel‐based inks are prepared by absorbing precursors of poly(acrylic acid) or poly(N‐isopropylacrylamide) in poly(acrylamide) (PAAm) microgels, and jamming them. The inks exhibit shear‐thinning and self‐healing properties that allow extrusion of the inks through a nozzle and rapid stabilization after printing. Stimuli‐mediated volume changes are observed for the extruded structures when they are post‐crosslinked by UV light to form interpenetrating networks of PAAm microgels and stimuli‐responsive hydrogels. Using this method, a dumbbell‐shaped object that can transform to a biconvex shape, and a gripper that can grasp and lift an object in response to stimuli are 3D‐printed. The jammed microgel‐based 3D printing strategy is a versatile method useful for variety of applications as diverse types of monomers absorbable in the microgels can be used to fabricate complex 3D objects transformable by external stimuli. Abstract : Jammed microgel‐based inks to fabricate complex structures transformable by external stimuli by extrusion‐based 3D printing are developed by absorbing precursors of stimuli‐responsive hydrogels to microgels. The inks exhibit shear‐thinning and self‐healing behaviors, ideal rheological properties for 3D printing. Interpenetrating networks of original microgels and stimuli‐responsive hydrogels formed in the 3D printed‐structures by post‐crosslinking mediate stimuli‐responsive structure changes of 3D objects.