A Composite Thermo‐Responsive Membrane System for Improved Controlled‐Release

A novel composite thermo‐responsive membrane system for improved controlled‐release is successfully developed. The membrane is composed of a porous membrane with grafted poly(N‐isopropylacrylamide) (PNIPAM) gates acting as functional valves, and a cross‐linked PNIPAM hydrogel inside the reservoir acting as the solute carrier. The thermo‐responsive controlled‐release characteristics of the proposed system are studied when the ambient temperature is continuously increased from 20 to 45 °C (across the LCST of PNIPAM) at a constant rate of 1.5 °C/min. The experimental results show that the prepared system exhibits significantly better performance for thermo‐responsive controlled‐release than single‐functional systems currently in existence, due to the cooperative action of the gating membrane and the inner cross‐linked hydrogel. Furthermore, due to the distinctive composite architecture, the proposed system can overcome some inherent disadvantages of current systems, such as the drug security problem of the reservoir‐type systems and the mechanical strength problem of the hydrogel matrix‐type systems. The system proposed in this study provides a new mode for thermo‐responsive controlled‐release.