In general, the halogen bond (XB) is a highly directional supramolecular interaction between a Lewis-acidic region of a covalently bound halogen (σ-hole) and a Lewis base. When compared to the familiar hydrogen bond (HB) interaction, the XB features a higher preference for linearity as well as a potential tuneability of the interaction strength, which constitutes the basis for XBs to be utilized in various fields of solution as well as solid state applications.<br/>While the usage of HBs in polymeric architectures has already been well established, recently also the combination of XB interactions and polymers has attracted growing interest with respect to the design of novel functional materials with on-demand properties. In this context, we provided the very first fundamental study dealing with the design of intrinsic self-healing polymer networks based on reversible XB formation. Therefore, we imbedded a series of 1,2,3-triazole / -triazolium based anion receptors into a polymeric architecture and studied their thermodynamic behavior in solution <i>via</i> isothermal titration calorimetry (Figure 1, right). Upon combination of these donor systems with a copolymer bearing accepting carboxylate groups, supramolecular crosslinked polymer networks were obtained showing excellent intrinsic self-healing behavior (Figure 1, left). Thereby, the XB-based induced crosslinking was clearly revealed by Raman spectroscopy as well as nanoindentation measurements.<br/>Consequently, the coupling of XBs with the concept of self-healing polymer networks allowed the formation of hard coatings characterized by a multiple self-healing capability at moderate temperatures.

Polymeric halogen-bond-based donor systems showing self-healing behavior in thin films

254th National Meeting (2017)

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