10.1021/acs.nanolett.9b02343.s001 Si Hyun Kim Si Hyun Kim Seungbae Oh Seungbae Oh Sudong Chae Sudong Chae Jin Woong Lee Jin Woong Lee Kyung Hwan Choi Kyung Hwan Choi Kyung Eun Lee Kyung Eun Lee Jongwha Chang Jongwha Chang Liyi Shi Liyi Shi Jae-Young Choi Jae-Young Choi Jung Heon Lee Jung Heon Lee Exceptional Mechanical Properties of Phase-Separation-Free Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup>‑Chain-Reinforced Hydrogel Prepared by Polymer Wrapping Process American Chemical Society 2019 nanowire gelatin matrix gelatin hydrogel Mo Polymer Wrapping Process Se Exceptional Mechanical Properties gelatin hydrogel exhibits 2019-08-05 21:03:28 Journal contribution https://acs.figshare.com/articles/journal_contribution/Exceptional_Mechanical_Properties_of_Phase-Separation-Free_Mo_sub_3_sub_Se_sub_3_sub_sup_sup_Chain-Reinforced_Hydrogel_Prepared_by_Polymer_Wrapping_Process/9252959 As Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup> chain nanowires have dimensions comparable to those of natural hydrogel chains (molecular-level diameters of ∼0.6 nm and lengths of several micrometers) and excellent mechanical strength and flexibility, they have large potential to reinforce hydrogels and improve their mechanical properties. When a Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup>-chain-nanowire-gelatin composite hydrogel is prepared simply by mixing Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup> nanowires with gelatin, phase separation of the Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup> nanowires from the gelatin matrix occurs in the micronetwork, providing only small improvements in their mechanical properties. In contrast, when the surface of the Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup> nanowire is wrapped with the gelatin polymer, the chemical compatibility of the Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup> nanowire with the gelatin matrix is significantly improved, which enables the fabrication of a phase-separation-free Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup>-reinforced gelatin hydrogel. The composite gelatin hydrogel exhibits significantly improved mechanical properties, including a tensile strength of 27.6 kPa, fracture toughness of 26.9 kJ/m<sup>3</sup>, and elastic modulus of 54.8 kPa, which are 367%, 868%, and 378% higher than those of the pure gelatin hydrogel, respectively. Furthermore, the amount of Mo<sub>3</sub>Se<sub>3</sub><sup>–</sup> nanowires added in the composite hydrogel is as low as 0.01 wt %. The improvements in the mechanical properties are significantly larger than those for other reported composite hydrogels reinforced with one-dimensional materials.