Simultaneously Toughening and Stiffening Elastomers with Octuple Hydrogen Bonding

Abstract

Current synthetic elastomers suffer from the well‐known trade‐off between toughness and stiffness. By a combination of multiscale experiments and atomistic simulations, a transparent unfilled elastomer with simultaneously enhanced toughness and stiffness is demonstrated. The designed elastomer comprises homogeneous networks with ultrastrong, reversible, and sacrificial octuple hydrogen bonding (HB), which evenly distribute the stress to each polymer chain during loading, thus enhancing stretchability and delaying fracture. Strong HBs and corresponding nanodomains enhance the stiffness by restricting the network mobility, and at the same time improve the toughness by dissipating energy during the transformation between different configurations. In addition, the stiffness mismatch between the hard HB domain and the soft poly(dimethylsiloxane)‐rich phase promotes crack deflection and branching, which can further dissipate energy and alleviate local stress. These cooperative mechanisms endow the elastomer with both high fracture toughness (17016 J m−2) and high Young's modulus (14.7 MPa), circumventing the trade‐off between toughness and stiffness. This work is expected to impact many fields of engineering requiring elastomers with unprecedented mechanical performance.

Recent Progress in Double Network Elastomers: One Plus One is Greater Than Two

“…For instance, Zhang et al. [ 52 ] presented a phase‐separation strategy for synthesizing transparent unfilled elastomers with both high stiffness and high toughness. Li et al.…”

Recyclable, Self‐Healing Solid Polymer Electrolytes by Soy Protein‐Based Dynamic Network

“…The bimodal composition of the N 1s narrow scan XPS spectrum (Figure 1e and Figure S5, Supporting Information) confirms the presence of bound N–H and free N–H groups (bound N–H groups have lower binding energy than free N–H groups). [ 22 ] According to their temperature‐sensitive characteristics, temperature‐dependent infrared spectroscopy provided evidence of the existence of supermolecular hydrogen bonds at the interface, as shown in Figure 1f,g (Figure S6, Supporting Information). [ 23,24 ] When the temperature raised from 30 °C to 120 °C, the intensities of the amino stretching vibrations at 3392.8 and 1550.5 cm −1 declined with increasing temperature and gradually shifted to a low wavenumber of 3296.9 and 1543.1 cm −1 , respectively.…”

A Protein‐Like Nanogel for Spinning Hierarchically Structured Artificial Spider Silk

“…Crosslinking is one of the indispensable structural characteristics contributing to the strength and toughness of fibers. This is because the molecular chains are locked in the crosslinking network, [ 12 ] however, making it nonspinnable.…”

“…Crosslinking is one of the indispensable structural characteristics contributing to the strength and toughness of fibers. This is because the molecular chains are locked in the crosslinking network, [12] however, making it nonspinnable.Efforts have been made to spin a fiber from a linear polymer or a soluble precursor followed by an additional crosslinking step. [6,7,13] Moreover, novel spinning methods, such as wet spinning, [14,15] dry spinning, [16,17] micro fluidic spinning, [18][19][20] electro-spinning, [21,22] templating, [23] and dynamic crosslinked spinning, [24] have been developed.…”