Design of a Rubbery Carboxymethyl Cellulose/Polyacrylic Acid Hydrogel via Visible-Light-Triggered Polymerization

Abstract

Hydrogels, as soft and wet materials, have attracted great attention in the field of functional biomaterials. Most recently, the designed hydrogels, according to the energy dissipation principle, overcome the low mechanical strength, poor toughness, and limited recoverability of common hydrogels and show excellent mechanical properties. However, most of these novel designed hydrogels are lacking of instantaneous recovery and antifatigue properties. In this study, a mesoscopic inhomogeneous hydrogel consisting of carboxymethyl cellulose and polyacrylic acid is synthesized through a facile, one‐pot, visible‐light‐triggered polymerization. The prepared hydrogel can be stretched over 700% with fracture strength as high as 850 kPa, and shows a high elastic modulus (180 kPa). The microgel aggregated structure endows an efficient energy dissipation mechanism to the hydrogel. After the internal network structure stabilizing, the hydrogel exhibits a recovery time within 10 ms and over 92% resilience during impact and cyclic tensile tests, respectively. The hydrogel with such excellent mechanical properties can extend its application in biomaterial fields.

Strain‐Sensitive Performance of a Tough and Ink‐Writable Polyacrylic Acid Ionic Gel Crosslinked by Carboxymethyl Cellulose

“…The experimental data have revealed that the studied fluids possess a strong shear‐thinning non‐Newtonian rheological behavior. Consistent with the literature description, the visible light (wavelength 380–760 nm) is a more effective trigger than heat for the polymerization of AA, the gel precursor composed of certain amounts of AA, CMC, KCl, ceric ammonium nitrate (CAN), and water polymerized into an ionic gel within 1 min. Thus, combining with the rheological behavior of water–CMC–salts systems, the gel precursor could be used as a direct writable ink ( Figure A–C and Video S1, Supporting Information, writing ink was colored by methylene blue), and the facile one‐pot visible‐light‐triggered polymerization process could be exploited to fabricate ionic gel with arbitrary architecture.…”

“…It is found that the tensile strength reaches 1.33 MPa, the rupture strain is 816.4%, and the toughness calculated from the area under the stress–strain curve is 5.11 MJ m −3 . These mechanical performances are comparable with that of the hydroxypropyl cellulose/polyvinyl alcohol composite hydrogel, and higher than that of the hydrogel (PAA/CMC) without KCl (fracture strength was 850 kPa, elongation at break was 700%) . This improvement may be attributed to the denser hydrogen bond among polymers due to the addition of mineral salt, giving rise to more extensive crosslinking, and consequently, enabling more prominent mechanical strength.…”

“…Recently, Zhu et al have reported a stretchable and tough hydrogel synthesized by incorporating two types of crosslinking interactions . A radical polymerization of acrylic acid (AA) was triggered by visible light radiating, curling carboxymethyl cellulose (CMC) was exploited as a crosslinker and co‐initiator.…”

Possible Application of Tough Hydrogel in Machinery

“…Recently, our group report a method of preparing a rubbery carboxymethyl cellulose/polyacrylic acid (CMC/PAA) hydrogel through a facile, one-pot, visible-light-triggered polymerization [5]. The tensile strength, fracture elongation, and modulus of the hydrogel are 400-850 kPa, 350-700%, and 65-180 kPa, respectively.…”

A high modulus hydrogel obtained from hydrogen bond reconstruction and its application in vibration damper

“…In our previous study, we prepared a carboxymethyl cellulose/polyacrylic acid hydrogel with excellent mechanical properties (tensile strength of 0.85 MPa, fracture elongation of 700%, and modulus of 0.18 MPa) by a facile, visible-light-triggered, one-pot polymerization method. 15,16 Herein, a aluminum ion cross-linked hydrogel (Gel) was synthesized by the same method, and then, the as-prepared Gel was reinforced via the evaporation-swelling method (E-S method) to obtain the high-modulus hydrogels (HM-Gel), with a tensile strength of 1.26-1.74 MPa and an elastic modulus of 0.59-1.94 MPa. In addition, both Gel and HM-Gel exhibited improved damping performance due to the presence of aluminum ion as a reinforcement cross-linking site; thus, the applicability of the hydrogel as a vibration control material is greatly improved.…”