Insights into the Mechanism of Polymer Coating Self-Healing Using Raman Spectroscopy

Abstract

Self-healing polymer coatings are an emerging class of smart materials. Upon mechanical damage the material properties may be restored by self-healing, which can be triggered externally, e.g., by an increased temperature. An alternative approach relies on embedding capsules with repair agents into the polymers, the rupture of which is induced by the mechanical damage, and the release of the repair agents triggers the self-repair reaction. The work at hand presents in situ Raman spectroscopic investigations on the reaction dynamics in such self-healing polymer coatings. Analysis of the Raman spectra allows one to assign specific Raman bands characteristic for the progress of the self-healing reaction.

Handheld Raman Spectroscopy for the Distinction of Essential Oils Used in the Cosmetics Industry

“…It has several applications in chemistry, physics and biology, highlighting studies on the composition of materials in different areas, such as microbiology, arts, archaeology, geology and atmospheric sciences, among many others [17][18][19][20][21][22][23][24]. Since handheld Raman spectrometers with short acquisition times and reasonable spectral resolutions are available, the applicability of this technique in industry has remarkably increased.…”

Improving Kinetics of “Click-Crosslinking” for Self-Healing Nanocomposites by Graphene-Supported Cu-Nanoparticles

“…[1,3,4,5,6,7,8,9,10], copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC)- (….) [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27], isocyanate- [28,29,30,31,32,33,34,35,36,37], thiol- [38,39,40,41,42,43,44,45,46] and hydrosilylation-chemistry [47,48], many of them using metal-catalysis.…”

Two-dimensional Raman correlation spectroscopy reveals molecular structural changes during temperature-induced self-healing in polymers based on the Diels–Alder reaction

“…With this in mind it comes as no surprise that a large amount of self-healing polymers based on the Diels-Alder reaction are reported. 2,15,[21][22][23][24] In this context vibrational spectroscopy such as, e.g., Raman spectroscopy is especially noteworthy since the probing of molecular vibrations grants direct insight into the molecular reactions taking place during the macroscopic self-healing process. Early approaches incorporated the diene or dienophile into the polymer molecules and used multifunctional small molecules to crosslink the strands.…”

“…[1][2][3][4][5]18,19 The [4+2]-cycloaddition is used in different approaches to introduce the self-healing function into polymers. 15,22 Kupfer et al used a combination of resonance Raman measurements and density functional theory (DFT) calculations to unveil the mechanisms involved in the self-healing of supramolecular polymers. 1,3,5,20 Recently, the attention shifted to polymers where diene and dienophile are covalently integrated into the same polymer (one-component-system).…”

“…To analyse the chemical mechanisms involved in self-healing and to improve self-healing materials in detail, spectroscopic studies on self-healing polymers are important. 2,15,[21][22][23][24] In this context vibrational spectroscopy such as, e.g., Raman spectroscopy is especially noteworthy since the probing of molecular vibrations grants direct insight into the molecular reactions taking place during the macroscopic self-healing process. 15,22 Kupfer et al used a combination of resonance Raman measurements and density functional theory (DFT) calculations to unveil the mechanisms involved in the self-healing of supramolecular polymers.…”