A highly stretchable, ultra-tough, remarkably tolerant, and robust self-healing glycerol-hydrogel for a dual-responsive soft actuator

Abstract

A novel strategy to synthesize a glycerol-hydrogel with high stretchability, ultra-toughness, remarkable tolerance, and outstanding self-healing capability has been developed. A soft actuator has been fabricated based on the glycerol-hydrogel.

Highly Swellable and Stretchable Thermoresponsive Hydrogels Enabled by Functionalized Boron Nitride Nanosheets

“…To improve the hydrophilicity and the interactions between the BNNSs and the polymer matrix, PNIPAM brushes were grafted onto the surface of BNNSs through ARGET ATRP to form f‐BNNSs. [ 21 ] Consequently, the MAH‐β‐CD and N ‐isopropylacrylamide (NIPAM) were added into the f‐BNNS solution followed by adding potassium persulfate (KPS), N,N ′‐methylene bis(acrylamide) (BIS), and tetramethyl ethylenediamine (TEMED). Finally, the P(MAH‐β‐CD‐ co ‐NIPAM)/f‐BNNS composite hydrogel was obtained by carrying out the gelation at 10 °C for 24 h. In the P(MAH‐β‐CD‐ co ‐NIPAM) copolymer, the cyclodextrin groups and isopropyl group served as host and guest molecules, respectively, leading to strong host–guest interactions within the whole copolymer.…”

“…[ 24 ] On the other hand, the dynamic interactions between f‐BNNSs and polymer matrix acted as sacrificial bonds to dissipate energy efficiently. [ 2,21 ]…”

“…BNNSs were prepared and characterized according to the previous work. [ 21–38 ] NIPAM (99%), copper(I) bromide (CuBr, 99.99%), N,N,N ′ ,N ″ ,N ″‐pentamethyldiethylenetriamine (PMEDTA), ascorbic acid, α‐bromoisobutyryl bromide (BiBB), N , N ‐dimethylformamide (DMF, 99%), MAH (99%), β‐CD, and TEMED (99%) were purchased from Sigma–Aldrich. KPS and BIS were provided by Aladdin Industrial Corporation.…”

“…In our previous work, poly(2‐acrylamido‐2‐methylpropane sulfonic acid)‐functionalized BNNSs were prepared through activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP), and the functionalized‐BNNSs as reinforced nanofillers to fabricate poly(acrylamide‐ co ‐maleic anhydride) hydrogel. [ 21–23 ] Interestingly, this designed strategy enables the hydrogel exhibit excellent strength and stretchability simultaneously, which was attributed to functionalized‐BNNSs to have excellent hydrophilicity and have strong interactions with the polymer matrix. [ 21 ] Herein, PNIPAM‐functionalized BNNSs (f‐BNNSs) were prepared by the same method, and a facile strategy was demonstrated to effectively improve the mechanical and swelling properties of the hydrogel by introducing f‐BNNSs into poly(maleic anhydride‐functionalized β‐cyclodextrin‐ co ‐ N ‐isopropylacrylamide (P(MAH‐β‐CD‐ co ‐NIPAM)) hydrogel.…”

“…[ 21–23 ] Interestingly, this designed strategy enables the hydrogel exhibit excellent strength and stretchability simultaneously, which was attributed to functionalized‐BNNSs to have excellent hydrophilicity and have strong interactions with the polymer matrix. [ 21 ] Herein, PNIPAM‐functionalized BNNSs (f‐BNNSs) were prepared by the same method, and a facile strategy was demonstrated to effectively improve the mechanical and swelling properties of the hydrogel by introducing f‐BNNSs into poly(maleic anhydride‐functionalized β‐cyclodextrin‐ co ‐ N ‐isopropylacrylamide (P(MAH‐β‐CD‐ co ‐NIPAM)) hydrogel. The f‐BNNSs were introduced to this hydrogels (named P(MAH‐β‐CD‐ co ‐NIPAM)/f‐BNNS hydrogel) because the PNIPAM segment of f‐BNNS could be attached to P(MAH‐β‐CD) segment by host–guest interactions to dissipate energy.…”