Silica/polymer double-walled hybrid nanotubes: synthesis and application as stimuli-responsive nanocontainers in self-healing coatings.

We report the development of silica/polymer double-walled hybrid nanotubes, which consist of a hollow cavity, a porous silica inner wall, and a stimuli-responsive (pH, temperature, and redox) polymeric outer wall, as a novel nanocontainer system. The length, diameter, wall thickness, and aspect ratio of the hybrid nanotubes are precisely controlled in the range of 48-506 nm, 41-68 nm, 3-24 nm, and 1.2-7.6, respectively. The hybrid nanotubes loaded with active molecules exhibit morphology-dependent release and pH-, temperature-, redox-responsive release, which enable a wide range of applications from energy storage to drug delivery and self-healing coatings for metal corrosion protection.