Development of cohesive self-healing gels based on self-assembly of organic and inorganic nanoparticles

Noncovalent bonds are often reversible and sensitive to external stimuli. Although noncovalent interactions are inherently weak and generally perceived as inadequate to construct macroscopic materials of sufficient integrity and cohesion, the emergence of nanotechnology has shown that the intrinsic weakness of noncovalent interactions can be compensated by maximizing the number of these bonds that work in concert. In that way, remarkably strong materials can be formed. colloidal gels are an emerging and particularly attractive class of cohesive hydrogels. These materials allow for “bottom-up” design of functional materials by employing noncovalent interactions between micro- or nanoscale particles as building blocks to assemble into shape-specific bulk materials. In an attempt to explore the feasibility of using electrostatic and hydrophobic interactions between nanoparticles, it was recently observed that colloidal gels made of oppositely charged gelatin nanospheres were surprisingly cohesive, elastic and self-healing. In the current study, we aim to extend this concept towards self-healing colloidal gels by synthesizing organic nanoparticles that exhibit a strong affinity for inorganic nanoparticles using various types of bioinspired derivatization strategies. The organic nanoparticles impart flexibility and resilience to these gels, while the inorganic nanoparticles improve their hardness and rigidity.