PT  - JOURNAL ARTICLE
AU  - Lin, Shaoting
AU  - Liu, Xinyue
AU  - Liu, Ji
AU  - Yuk, Hyunwoo
AU  - Loh, Hyun-Chae
AU  - Parada, German A.
AU  - Settens, Charles
AU  - Song, Jake
AU  - Masic, Admir
AU  - McKinley, Gareth H.
AU  - Zhao, Xuanhe
TI  - Anti-fatigue-fracture hydrogels
AID  - 10.1126/sciadv.aau8528
DP  - 2019 Jan 01
TA  - Science Advances
PG  - eaau8528
VI  - 5
IP  - 1
4099  - http://advances.sciencemag.org/content/5/1/eaau8528.short
4100  - http://advances.sciencemag.org/content/5/1/eaau8528.full
SO  - Sci Adv2019 Jan 01; 5
AB  - The emerging applications of hydrogels in devices and machines require hydrogels to maintain robustness under cyclic mechanical loads. Whereas hydrogels have been made tough to resist fracture under a single cycle of mechanical load, these toughened gels still suffer from fatigue fracture under multiple cycles of loads. The reported fatigue threshold for synthetic hydrogels is on the order of 1 to 100 J/m2. We propose that designing anti-fatigue-fracture hydrogels requires making the fatigue crack encounter and fracture objects with energies per unit area much higher than that for fracturing a single layer of polymer chains. We demonstrate that the controlled introduction of crystallinity in hydrogels can substantially enhance their anti-fatigue-fracture properties. The fatigue threshold of polyvinyl alcohol (PVA) with a crystallinity of 18.9 weight % in the swollen state can exceed 1000 J/m2.