Self-healing polyacrylates based on dynamic disulfide and quadruple hydrogen bonds

Herein, a self-healing polyacrylate system was successfully prepared by introducing crosslinking agents containing disulfide bonds and monomers capable of forming quadruple hydrogen bonds through free radical copolymerization. This polymer material exhibited good toughness and self-healing properties through chemical and physical dual dynamic networks while maintaining excellent mechanical properties, which expanded the development path of self-healing acrylate materials. Compared to uncrosslinked and single dynamically crosslinked polymers, its elongation at break was as high as 437%, and its tensile strength was 5.48 MPa. Due to the presence of dual reversible dynamic bonds in the copolymer system, good self-healing was also achieved at 60 °C. In addition, differential scanning calorimetry and thermogravimetric analysis measurements confirmed that the thermal stability and glass transition temperature of the material were improved owing to the presence of physical and chemical cross-linking networks.

Preparation and properties of water-based acrylic emulsion-assisted flexible building tiles

The heavy and rigid appearance of conventional burnt building tiles is not suitable for a global sustainable development strategy. Flexible facing tiles with lightweight and environmental materials are highly desirable for the construction industry today. In this work, water-based polymer emulsion-assisted flexible building tiles were prepared. Based on the method of achieving post crosslinking and improving adhesion with inorganic matrix-based materials, WPAs modified with GMA and KH570 display good chemical resistance and low solvent absorption (0.132 in water and 0.289 in ethanol respectively). The optimum mechanical performance of flexible building materials prepared with WPAs can strain 1.406% and stress 1.8658 MPa. The TGA, XRD, SEM and AFM results further indicate the excellent thermal stability and compatibility of flexible building tiles. Hence, flexible building tiles prepared with WPAs can be promising building materials for construction.

Self-healing hydrophobic POSS-functionalized fluorinated copolymers via RAFT polymerization and dynamic Diels–Alder reaction

Development of self-healing hydrophobic POSS-functionalized fluorinated copolymethacrylate(s) via RAFT Polymerization and dynamic Diels–Alder Reaction.

Construction of a thermoreversible chemical crosslinking network – a new exploration for the efficient reusability of commercial rubber

A thermoreversible rubber DSBR was prepared via a reaction between a nitroxide-based crosslinker and commercial styrene–butadiene rubber. Impressive recoveries of mechanical properties of DSBR were achieved for the alkoxyamine crosslinking network.

Self-Healing in Mobility-Restricted Conditions Maintaining Mechanical Robustness: Furan-Maleimide Diels-Alder Cycloadditions in Polymer Networks for Ambient Applications

Two reversible polymer networks, based on Diels–Alder cycloadditions, are selected to discuss the opportunities of mobility-controlled self-healing in ambient conditions for which information is lacking in literature. The main methods for this study are (modulated temperature) differential scanning calorimetry, microcalorimetry, dynamic rheometry, dynamic mechanical analysis, and kinetic simulations. The reversible network 3M-3F630 is chosen to study the conceptual aspects of diffusion-controlled Diels–Alder reactions from 20 to 65 °C. Network formation by gelation is proven and above 30 °C gelled glasses are formed, while cure below 30 °C gives ungelled glasses. The slow progress of Diels–Alder reactions in mobility-restricted conditions is proven by the further increase of the system’s glass transition temperature by 24 °C beyond the cure temperature of 20 °C. These findings are employed in the reversible network 3M-F375PMA, which is UV-polymerized, starting from a Diels–Alder methacrylate pre-polymer. Self-healing of microcracks in diffusion-controlled conditions is demonstrated at 20 °C. De-gelation measurements show the structural integrity of both networks up to at least 150 °C. Moreover, mechanical robustness in 3M-F375PMA is maintained by the poly(methacrylate) chains to at least 120 °C. The self-healing capacity is simulated in an ambient temperature window between −40 and 85 °C, supporting its applicability as self-healing encapsulant in photovoltaics.

Molecular Aggregation Structure and Surface Properties of Biomimetic Catechol-Bearing Poly[2-(perfluorooctyl)ethyl acrylate] and Its Application to Superamphiphobic Coatings

The molecular aggregation structure and surface properties of a catechol-bearing fluoropolymer, P(FAC8-co-DOPAm), which was synthesized by conventional radical copolymerization of 2-(perfluorooctyl)ethyl acrylate (FAC8) and N-(3,4-dihydroxyphenethyl)acrylamide (DOPAm), and its application to the superamphiphobic surfaces are presented. The crystallinity of P(FAC8-co-DOPAm) was lower than that of poly[2-(perfluorooctyl)ethyl acrylate] (PFAC8). The perfluoroalkyl (Rf) groups were ordered on the surface with CF3 terminals exposed to air, and the Rf ordering was influenced by thermal history: the thermally annealed film exhibited higher Rf ordering than the unannealed one. The surface free energy was estimated to be γ = 7.32 mJ m-2 for both the unannealed and annealed films. Based on contact angle measurement, various interfacial structures of water and oils in accordance with the surface aggregation structure of Rf groups were proposed. Dewetting of the PFAC8 film at elevated temperature was suppressed by the introduction of catechol groups in the backbone. The degradation temperature of PFAC8 was improved significantly, and the evaporation of the low molar mass-polymer was inhibited by the introduction of catechol groups under both nitrogen and air atmospheres. The hydrophobicity of the copolymer films could be healed after the surface was damaged by vacuum ultraviolet (VUV) irradiation. This copolymer was used to create superamphiphobic fabrics and halloysite nanotube (HNT)-based organic/inorganic hybrid coatings successfully. Wetting behaviors of the superamphiphobic fabrics and coatings both follow the Cassie-Baxter wetting model.

Functional fluorinated polymer materials and preliminary self-healing behavior

Effective use of Diels–Alder chemistry led to the development of thermally amendable and self-healing polymeric materials based on a copolymer of cyclopenta-1,3-dien-1-ylmethyl 2-(trifluoromethyl)acrylate (MAF-Furan) and 2,2,2-trifluoroethyl α-fluoroacrylate (FATRIFE).