Retention of poly(N‐isopropylacrylamide) thin films on polycarbonate via polymer interdiffusion

This study explored the possibility of polymer interdiffusion for retaining thermoresponsive poly(N‐isopropylacrylamide) (pNIPAAm) on polycarbonate (PC). It was hypothesized that interdiffusion could be facilitated either by increasing the annealing temperature or by treating PC using air plasma (AP) and ultra‐violet ozone (UVO). The results showed that increasing annealing temperature only moderately improved pNIPAAm retention. Treating PC with AP led to an increase in surface‐active groups and a greatly enhanced retention of pNIPAAm. UVO treatment, however, severely damaged the PC layer with no noticeable enhancement on pNIPAAm retention. The retained pNIPAAm films on PC exhibited thermoresponsive behavior as evidenced by water contact angle and desired cell attachment/detachment behaviors. These results illustrate the simplicity of using polymer interdiffusion to successfully retain pNIPAAm films on a polymer, and the resulting substrates would be less expensive and more versatile than those retained on brittle supports (e.g., glass) for applications that require resilient thermoresponsive substrates. The retention of thermoresponsive poly(N‐isopropylacrylamide) (pNIPAAm) on ductile polycarbonate (PC) utilizing polymer interdiffusion was investigated. By optimizing the oxidization extent (air plasma) of PC, interdiffusion between the two polymers was enhanced to attain pNIPAAm with suitable thicknesses for desired cell attachment/detachment by temperature switching. The simplicity of this approach provides a cost‐effective alternative to laborious grafting or polymerization based methods for fabricating thermoresponsive supports using inexpensive/resilient polymers, which are highly sought‐after in regenerative medicine