Correlation between scratch healing and rheological behavior for terpyridine complex based metallopolymers

Abstract

The healing phenomenon of metallopolymers is studied in detail and the dependency of the chosen metal salt is provided. Furthermore, a correlation between the supramolecular bond life time and the healing behavior could be revealed.

Intrinsic self-healing polymers with a high E-modulus based on dynamic reversible urea bonds

“…This material was obtained after the bulk polymerization of BMA and 1,6-hexanediol dimethacrylate according to procedures reported in the literature. 23 The degree of crosslinking was 5% and, thus, was comparable with P1.…”

“…Furthermore, P4, the reference polymer without any reversible moiety, featured no scratch-healing ability, as reported in the literature. 23 In addition to the scratch-healing tests, tensile testing was performed. For this purpose, the above-described bulk polymerization was performed in a Teflon mold to obtain dog bone-shaped specimens (Supplementary Information; Supplementary Figure S22).…”

“…23 The pure PBMA, which was only utilized as a model substance for the Raman measurements, was also synthesized according to the previous literature reports. 16 Dissolution experiments of P1 in aniline.…”

“…6 These binding motifs can be composed of either dynamic covalent bonds, [7][8][9] for example, the Diels-Alder reaction [10][11][12] or radical-based systems, 13 or supramolecular interactions, such as hydrogen or halogen bonds, [14][15][16] ionic interactions, 17 π-π interactions, 18 host-guest interactions 19 or metal-ligand interactions. [20][21][22][23] Often there is a trade-off between the mechanical properties and the healing efficiency (Figure 1). High healing efficiencies are mostly only possible for low E-moduli; for E-moduli above 10 7 -10 8 Pa, the number of reported examples decreases significantly, as well as the achieved healing efficiencies.…”

Stress intensification – an abnormal phenomenon observed during stress relaxation of dynamic coordination polymer

“…As a result, the frequency dependence of storage shear modulus, G′, of the water saturated specimen intersects with that of loss shear modulus, G″, suggesting a transition from elastic-like (G′ > G″) to viscous-like (G′ < G″) with decreasing frequency (Figure 4a). Since the disconnected networks need time to be reconnected, the system has to perform like viscous fluid at low frequency regime [12][13][14]. In contrast, the dry HBPU-DMPA-[Fe(DOPA) 3 ] (Figure 4b) and the control without Fe 3+ (Figure 4c) do not exhibit the same network reconfiguration due to lack of the dynamic bonds.…”