In this work, we produce thin films of hydrogel-like polymers for potential bio-applications. Poly(ethylene glycol) (PEG) is a technologically important polymer with many biomedical applications including tissue engineering, drug delivery, non-biofouling membranes and spatial patterning of cells. In this work, we created PEG thin films by iCVD without the use of solvents. We also created thin films of poly(2-hydroxyethyl methacrylate) (PHEMA), which is a hydrogel and does not dissolve in water. In addition to synthesis of homopolymers of PEG and PHEMA we also synthesized copolymers of PEG-PHEMA. Depending on the composition, PEG–PHEMA block copolymers may be water soluble or water insoluble. The presence of a second monomer gives us the freedom to change many variables including the percentage of each monomer.
Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies showed that the chemistry of PEG obtained by iCVD synthesis matched closely to PEG obtained from solution synthesis. The effect of substrate temperature, system pressure and reactant flowrates were studied to develop a kinetic model for the iCVD of PHEMA and PEG. This work showed that iCVD can be used to create copolymers of PEG-PHEMA. Cationic polymerization of PEG as well as copolymerization in vapor phase was shown to correspond well to those in the liquid phase. This work demonstrates that iCVD can directly apply liquid polymerization chemistries with great versatility.