Light‐Fueled, Spatiotemporal Modulation of Mechanical Properties and Rapid Self‐Healing of Graphene‐Doped Supramolecular Elastomers

Abstract

Gaining spatially resolved control over the mechanical properties of materials in a remote, programmable, and fast-responding way is a great challenge toward the design of adaptive structural and functional materials. Reversible, temperature-sensitive systems, such as polymers equipped with supramolecular units, are a good model system to gain detailed information and target large-scale property changes by exploiting reversible crosslinking scenarios. Here, it is demonstrated that coassembled elastomers based on polyglycidols functionalized with complementary cyanuric acid and diaminotriazine hydrogen bonding couples can be remotely modulated in their mechanical properties by spatially confined laser irradiation after hybridization with small amounts of thermally reduced graphene oxide (TRGO). The TRGO provides an excellent photothermal effect, leads to light-adaptive steady-state temperatures, and allows local breakage/de-crosslinking of the hydrogen bonds. This enables fast self-healing and spatiotemporal modulation of mechanical properties, as demonstrated by digital image correlation. This study opens pathways toward light-fueled and light-adaptive graphene-based nanocomposites employing molecularly controlled thermal switches.

Healable and Mechanically Super‐Strong Polymeric Composites Derived from Hydrogen‐Bonded Polymeric Complexes

“…Polymeric complexes can be produced by mixing polymers with complementary noncovalent interactions in bulk solution or sequentially at interface of solid substrates and polymer solutions . Given that various polymers bearing complementary interactions can be employed to prepare polymeric complexes, polymeric composite materials based on polymeric complexes can possess various compositions, controllable cross‐linking density, and well‐tailored mechanical properties .…”

“…During the formation of polymeric complexes, polymers with self‐assembly ability can generate well‐designed micro‐/nanosized structures, which provide a facile way to further tailor the mechanical properties of the resultant materials . Similar to supramolecular polymers, the reversible noncovalent interaction among polymer chains can also endow polymeric composite materials composed of polymeric complexes with satisfactory healing capability . Polymer composites based on polymeric complexes exhibit several distinctive advantages over supramolecular polymers which include simple preparation, low cost, and high‐yield production .…”

The Past 40 Years of Macromolecular Sciences: Reflections on Challenges in Synthetic Polymer and Material Science

“…Materials with self‐healing properties can be designed by incorporating noncovalent bonds into polymers and subsequently be tuned within certain borders to achieve different material strengths and healing times . The true art of molecular engineering of self‐healing polymers is to achieve autonomous healing close to room temperature (e.g., involving H‐bonds at 30 °C) in contrast to “healing” at elevated temperatures (e.g., at 140 °C by laser‐NIR‐irradiation). Autonomous healing, thus, is truly difficult to design, as the actual dynamics of the supramolecular bonds in polymers and materials are only sparsely understood, being entirely different from the picture commonly observed in solution chemistry .…”

Thermoreversible Polymeric Nanocomposites

“…Hydrogen bonding [11][12][13][14] and ionic interactions [9] have been often used as thermally reversible interactions for composites of different kinds. One of the main driving forces behind the use of such a strategy is the presence of special end properties.…”

“…One of the main driving forces behind the use of such a strategy is the presence of special end properties. For example, the dynamic nature of thermally reversible interactions (as a function of temperature) endows composites with self-healing behavior [11,13,[15][16][17] and shape-memory characteristics [18,19].…”