Design Principles of Interfacial Dynamic Bonds in Self‐Healing Materials: What are the Parameters?

Abstract

Polymers and polymer nanocomposites (PNCs) are extensively used in daily life. However, the growing requirement of advanced PNCs laid persistent environmental issues due to deformation‐induced damage that once formed, does not vanish at future stages. Therefore, self‐healing materials with significantly enhanced long life and safety have been designed to epitomize the forefront of recent advances in materials chemistry and engineering. Self‐healing PNC (SH‐PNCs) materials are a class of smart composites in which nanoparticles induce interfacial reconstruction via multiple covalent and non‐covalent interactions culminating in improved mechanical strength and self‐healing capability. However, since the filler nanoparticles are independent of the reversible supramolecular network, the filler incorporation destroys the self‐healing ability but could enhance the mechanical strength. Hence, the molecular parameters controlling the alliance of robust mechanical strength with virtuous self‐healing ability is a crucial challenge. Herein, we review the latest developments that have been made in self‐healing materials and puts advancing insights into the fabrication of SH‐PNCs in which the combination of covalent bonds and non‐covalent interactions provides an optimal balance between their mechanical performance and self‐healing capability. We highlight the importance of specific entropic, enthalpic changes, polymer chain conformations and flexibility that enable the reconstruction of damaged surface and physical reshuffling of dynamic bonds at the interface of cut surfaces.

Preparation of Natural Rubber Composites with High Silica Contents Using a Wet Mixing Process

“…This trend was also observed by Wang et al The lower tan δ of WSR indicated high filler–filler interaction with low filler–rubber interaction . However, the filler–rubber interaction can be improved by using an interfacial modifier. , …”

“…Reinforcing fillers have been developed for rubber composite products to improve their quality characteristics such as the modulus, tensile strength, and abrasion resistance and are critical to practical rubber technology. Nowadays, the amount of the silica (SiO 2 ) filler used as an additive in the tire industry is continuously increasing because silica-reinforced rubber presents a low rolling resistance, low hysteresis, high hardness, and good abrasion resistance, and they are technical advantages over carbon black-filled rubber. , In addition, the improvement of the self-healing capability of the silica-filled rubber composite for extending its long life and safety was studied by several investigators. − …”

“…However, the main drawbacks of this method are high energy consumption and being time-consuming because of the high viscosity that makes the processing more difficult . Additionally, some silica is lost as silica dust spreading around the factory during conventional mixing. − Thus, a wet mixing process has been developed to overcome these drawbacks. Wet mixing of silica-filled natural rubber is a novel method for improving the silica dispersion in the rubber matrix, thereby achieving excellent mechanical properties of the vulcanizates.…”

Interface Structure and Dynamics in Polymer‐Nanoparticle Hybrids: A Review on Molecular Mechanisms Underlying the Improved Interfaces

“…Although understanding of the effects of filler NPs on a polymer matrix is crucial at the molecular level, [77–84] because of the limited laboratory techniques with a low‐resolution limit (1 to 100 nm), the atomistic physics behind the observed phenomena has remained unclear (Harding et al., 2008) [85] . Hence, the use of computational methods has developed progressively to realize materials assembly and performance (Heinz et al.,2016; Gunsteren et al., 2006; Heinz et al., 2013; and Huang et al., 2011) [20,86–88] .…”

Polymeric Emissive Materials Based on Dynamic Covalent Bonds

“…Dynamic interactions, including supramolecular interactions and dynamic covalent bonds (DCBs), can reversibly break down and build up, and well respond to external stimuli. Recently, dynamic interactions have been introduced into the polymer and endow the polymer with various advanced properties, such as self-healing, shape memory, adaptability, and stimuli-responsiveness [ 4 , 5 , 6 ]. Generally, there is a compromise between mechanical performance and dynamic behavior when dynamic interactions are introduced into the polymeric materials.…”