Interface assisted synthesis of complex hydrogel particles

We show that hydrogel particles could be easily synthesized by adding drops of aqueous solution containing monomer, comonomer, crosslinker, and initiator to the surface of a polytetrafluoroethylene (PTFE or Teflon) disk immersed in 2,2,4-trimethylpentane (TMP). This system yielded conditions that allowed for a spherical drop to be stable at that interface while the polymerization occurred. This approach was used to synthesize particles composed of poly(N-isopropylacrylamide) (pNIPAm) and poly(2-hydroxyethyl methacrylate) (pHEMA). Furthermore, the polymer particles could easily be doped with a variety of nanoparticles and small molecules simply by adding the components to the monomer/crosslinker solution prior to polymerization. This synthetic route is advantageous because it only appears to depend on the ability to form a water drop at the PTFE–TMP interface, thus this approach can be used to synthesize particles with a variety of different functionalities and compositions. This can lead to direct applications in oral drug delivery and tissue engineering.