Functional polymer-clay nanotube composites with sustained release of chemical agents

Natural halloysite clay nanotubes are described as inorganic reinforcing materials for polymers. Loading these tubes' 15-nm diameter lumens with chemical agents, including bioactive molecules (self-healing, anticorrosion, antimicrobial agents, proteins, DNA, drugs, etc.), and doping them into polymers allows a controlled sustained release, providing these nanocomposites with new smart properties. Typically, addition of 5% halloysite synergistically increases polymer strength on 30-70%, enhances composite adhesivity and adds new functions due to triggered release of needed chemicals. Halloysite is biocompatible “green” material and its simple processing combined with low cost make it a perspective additive for polymeric biocomposites. Comparison of halloysite with other tubule clay - imogolite - is given; these tubes have smaller diameter and much lower loading capacity for macromolecules.