Carbon Dots as Fillers Inducing Healing/Self‐Healing and Anticorrosion Properties in Polymers

Abstract

Self-healing is the way by which nature repairs damage and prolongs the life of bio entities. A variety of practical applications require self-healing materials in general and self-healing polymers in particular. Different (complex) methods provide the rebonding of broken bonds, suppressing crack, or local damage propagation. Here, a simple, versatile, and cost-effective methodology is reported for initiating healing in bulk polymers and self-healing and anticorrosion properties in polymer coatings: introduction of carbon dots (CDs), 5 nm sized carbon nanocrystallites, into the polymer matrix forming a composite. The CDs are blended into polymethacrylate, polyurethane, and other common polymers. The healing/self-healing process is initiated by interfacial bonding (covalent, hydrogen, and van der Waals bonding) between the CDs and the polymer matrix and can be optimized by modifying the functional groups which terminate the CDs. The healing properties of the bulk polymer-CD composites are evaluated by comparing the tensile strength of pristine (bulk and coatings) composites to those of fractured composites that are healed and by following the self-healing of scratches intentionally introduced to polymer-CD composite coatings. The composite coatings not only possess self-healing properties but also have superior anticorrosion properties compared to those of the pure polymer coatings.

Scalable Synthesis of Multifunctional Epidermis‐Like Smart Coatings

“…Healable polymeric smart coatings are a unique class of self‐healing materials due to their low‐dimensional nature, thin film structure, and substrate involved. Many dynamic or capsule‐based self‐healing coatings have been prepared in different systems including polydimethylsiloxane, polyethylenimine/polyacrylic acid, and polyurethane, just to name a few. To maintain the high flowability during self‐healing, these smart coatings are typically soft with sacrificed robustness .…”

Bio‐based epoxy/polyaniline nanofiber‐carbon dot nanocomposites as advanced anticorrosive materials

“…CDs are the fluorescent class of nanomaterials consisting of several oxygenous groups having size below 10 nm . CD has been extensively explored due to its unique set of properties like excellent photocatalytic activity, low toxicity, and good biocompatibility . Zhu et al .…”

“…CD has been extensively explored due to its unique set of properties like excellent photocatalytic activity, low toxicity, and good biocompatibility . Zhu et al . recently synthesized CD‐based nanocomposites with different bulk polymers and copolymers and their self‐healing and anticorrosion abilities were tested.…”

Negatively Charged Carbon Nanodots with Bacteria Resistance Ability for High‐Performance Antibiofilm Formation and Anticorrosion Coating Design

“…CDs are a versatile carbon nanomaterial derived from various natural sources with specific physicochemical properties, such as low/nontoxicity, good water solubility, and stability . In our recent work, we showed a pioneering work by applying nitrogen‐decorated CDs to initiate self‐healing and corrosion resistance properties of coatings . In this work, for the first time, we synthesized negatively charged CDs with abundant oxygen functional groups (COOH, OH, and CO) as a smart dual functional additive in polyurethane (PU) coatings that simultaneously initiates antibiofilm formation and anticorrosion (about 60 days' durability in seawater) properties.…”

“…These results indicate the optimal quantity/density of CDs inside the PU has the most stable electronic status and the best blocking effect (lowest ionic conduction) against the aggressive species like water and oxygen molecules. A stable electronic status of CDs‐PU could reduce the probability of Fe atom to lose electrons to form Fe 2+ or Fe 3+ , whereas the blocking effect is related with the abundant functional groups of CDs, which can connect with the PU chains through hydrogen bonding to reduce the formation and prevent the expansion of micropores/capillaries, effectively obstructing crossing oxygen and water through defects paths …”