Design and construction of high strength double network hydrogel with flow-induced orientation

• Published in: Journal of colloid and interface science 2024-10, Vol.672, p.497-511
• Main Authors: Guo, Li, Ji, Cheng, Wang, Haiwang, Ma, Tianxiao, Qi, Jian
• Format: Article
• Language: English
• Subjects: Alginate; Double network hydrogel; Inorganic phase toughening; Micro orientation; Polyacrylamide
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2024.06.046

Using a syringe, the precast gel solution—which included acrylamide, sodium alginate, and modified titanium dioxide nanofibers—was extruded into the CaCl2 solution to create the sodium alginate first network. The second network of polyacrylamide(PAM) was subsequently created by photocatalysis. Ultimately, the alginate/PAM/TiO2NF@PAM composite hydrogel improved by the inorganic phase was produced. It has mechanical properties with a tensile ratio of 166% and a tensile strength of 1.13 Mpa. [Display omitted] •Alginate/polyacrylamide/modified TiO2 nanofiber (Alginate/PAM/TiO2NF@PAM) composite hydrogel was successfully designed and synthesized.•The three toughening strategies of dual network, construction of oriented structure, and nanophase doping were successfully combined.•Alginate/PAM/TiO2NF@PAM showed a tensile ratio of (165.51 ± 4.93)% and a maximum tensile strength of (1130.97 ± 67.39) kpa. The design and construction of high strength hydrogels is a widely discussed topic in hydrogel research. In this study, we combined three toughening strategies, including dual network, oriented structure construction and nanophase doping, to develop an alginate/polyacrylamide (PAM)/modified titanium dioxide fiber (TiO2 NF@PAM) dual network composite hydrogel prepared via syringe. The effects of different preparation methods, AM/Alginate ratios, inorganic doping phases and TiO2 NF@PAM/AM ratios on the mechanical properties of composite hydrogels were investigated. The study found that the alginate hydrogel prepared by syringe exhibited superior axial orientation and achieved a tensile strength of (1091 ± 46) kPa. And the composite hydrogel doped with 0.2 wt% TiO2 NF@PAM had a tensile strength of (1006 ± 64) kPa, which was higher than that of the composite hydrogel doped with 0.2 wt% TiO2 nanoparticles (976 ± 66) kPa. The highest tensile strength (1120 ± 67) kPa and elongation at break (182 ± 8) % were achieved when the ratio of TiO2 NF@PAM/AM was 0.6 wt%. The force applied to the gel solution in the syringe affects the orientation of the polymer chains and TiO2 NF@PAM within the gel, which subsequently impacts the mechanical properties of the hydrogel. Therefore, we further investigated the mechanical properties of composite hydrogels under varying propulsion speeds, syringe diameters, and syringe lengths. It was observed that the gel solution’s shear strength increased as the syringe diameter decreased. The resulting composite hydrogels were better oriented and had i