Bulk Energy Dissipation Mechanism for the Fracture of Tough and Self-Healing Hydrogels

• DOI: 10.1021/acs.macromol.7b00162
• Publication Date: 2017-03-29T18:07:41Z
• Authors: Tao Lin Sun; Feng Luo; Wei Hong; Kunpeng Cui; Yiwan Huang; Hui Jie Zhang; Daniel R. King; Takayuki Kurokawa; Tasuku Nakajima; Jian Ping Gong
• Keywords: Time–temperature superposition; Elastic energy; Exponent

Recently, many tough and self-healing hydrogels have been developed based on physical bonds as reversible sacrificial bonds. As breaking re-forming of are time-dependent, these viscoelastic the deformation rate temperature pronouncedly influence their fracture behavior. Using a polyampholyte hydrogel model system, we observed that time–temperature superposition principle is obeyed not only for small strain rheology but also large hysteresis energy dissipation below certain temperature. The three processes possess same shift factors obey equation Williams, Landel, Ferry (WLF) equivalence. Γ scales with crack velocity Vc over wide range ∼ Vcα (α = 0.21). exponent α power law well-related to κ relaxation modulus G(t) t–κ (κ 0.26), obeying prediction κ/(1 + κ) from classic viscoelasticity theory. These results show gel dominated by bulk dissipated around tip. This investigation gives an insight into designing predicting behaviors dynamic mechanical spectrum.