Anchoring PNIPAM on ATP Surface via hydrogen bonding and coordination for a temperature-responsive adsorption of hydrophobic drug

A thermo-responsive polymer, poly(N-isopropylacrylamide) (PNIPAM), was anchored on the surface of low-cost natural clay nanorods, attapulgite (ATP), through the interactions including hydrogen bonding and coordination. Premixing the monomers of NIPAM with ATP before polymerization caused that the obtained PNIPAM could distribute among the pore voids of ATP and function as a surface affinity conditioner in response to temperature change. The PNIPAM/ATP composite was then applied in temperature-triggered adsorption and desorption of a hydrophobic drug (typically, an agricultural pesticide: acetamiprid). The results indicated a satisfactory adsorption capacity and reusability with the strong combination of PNIPAM and ATP. Furthermore, the adsorption mechanism was discussed, and the Sips model was employed to explain the adsorption behavior. It was proved to be beneficial for hydrophobic drug loading as well as its delivery, which may also have a potential to extend to other natural products and responsive polymers.