Chang Seo Park1,Hyeonuk Na1,Yong-Woo Kang1,Sohyun Jung2,Ho-Young Kim3,Jeong-Yun Sun4,5
Multi-Functional Soft Materials Laboratory Department of Materials Science and Engineering1,SOFT FOUNDRY, Seoul National University2,Department of Mechanical Engineering, Seoul National University3,Department of Material Science and Engineering, SeoulNational University4,Research Instituteof Advanced Materials (RIAM), Seoul National University5
Chang Seo Park1,Hyeonuk Na1,Yong-Woo Kang1,Sohyun Jung2,Ho-Young Kim3,Jeong-Yun Sun4,5
Multi-Functional Soft Materials Laboratory Department of Materials Science and Engineering1,SOFT FOUNDRY, Seoul National University2,Department of Mechanical Engineering, Seoul National University3,Department of Material Science and Engineering, SeoulNational University4,Research Instituteof Advanced Materials (RIAM), Seoul National University5
Hydrogels are promising as materials for soft actuators because of qualities such as softness, transparency, and responsiveness to stimuli. However, weak and slow actuations remain challenging as a result of low modulus and osmosis-driven slow water diffusion, respectively. We used turgor pressure and electroosmosis to realize a strong and fast hydrogel-based actuator. A turgor actuator fabricated with a gel confined by a selectively permeable membrane can retain a high osmotic pressure that drives gel swelling; thus, our actuator exerts large stress [0.73 megapascals (MPa) in 96 minutes (min)] with a 1.16 cubic centimeters of hydrogel. With the accelerated water transport caused by electroosmosis, the gel swells rapidly, enhancing the actuation speed (0.79 MPa in 9 min). Our strategies enable a soft hydrogel to break a brick and construct underwater structures within a few minutes.