Surface control of layered double hydroxides by in-situ initiating & terminating polymerization

Appropriate surface modification or functionalization is prerequisite for the application of inorganic nanoparticles. And surface control between organic and inorganic interface plays an important role in constructing organic-inorganic composites. In-situ polymerization has been extensively studied to improve the compatibility and dispersibility of inorganic nanoparticles, but the polymerized nanoparticles tend to concatenate and form large composites, restricting further applications. Herein, uniform and dense polyacrylic acid (PAA) membranes have been grafted on layered double hydroxide (LDH) nanosheets via an in-situ initiating and terminating radical graft polymerization method. With initiating and terminating on the same particle, the size, morphology and density of grafted PAA onto the surface of LDHs can be controlled by adjusting the ratio of initiated sites to terminated sites, the amount of redox initiator or monomer. As a result, with only 17.33% organic grafting ratio, PAA@LDHs with largely improved compatibility can be monodispersed in polyethylene (PE) and polyvinyl chloride (PVC) matrices, which is determined by a fluorescence microscope technique.

Automated summary

This study successfully grafted uniform and dense PAA membranes onto LDH nanosheets using an in-situ initiating and terminating radical graft polymerization method. By adjusting the ratio of initiated sites to terminated sites, the amount of redox initiator or monomer, the size, morphology and density of grafted PAA on LDH surfaces can be controlled. This enables the monodispersion of PAA@LDHs in PE and PVC matrices with greatly improved compatibility.