Chemical Vapor Deposition Processing
DropWise uses solvent-free chemical vapor deposition (CVD) processes to apply functional polymer coatings. Parts to be coated are placed into a chamber that is then evacuated to below atmospheric pressure, and then gaseous precursor chemicals are introduced into the chamber. After precursor molecules are activated through exposure to heat, they adsorb to the substrate surface and undergo free radical polymerization. The result are coatings that polymerize on the surface of the substrates and grow from the surface up. During the entire process, the parts being coated are maintained at roughly room temperature.
Benefits of DropWise’s CVD Processes
Using solvent-free CVD processes, DropWise is able to apply coatings to substrates without the limitations and challenges experienced with dip and spray coatings. DropWise’s coating processes are non-line of sight, which allows us to conformally coat complex features at the macroscale down to the nanoscale. This enables us to preserve the shape of the underlying substrate rather than filling in features or having coatings that have significant thickness variations due to gravity effects. Additionally, we are able to apply our coatings deep within porous materials without clogging the pores. Lastly, the low-temperature and solvent-free processing is especially important for substrates that have temperature limits or chemical compatibility issues.
DropWise polymer coatings reach within even micro-porous materials like this porous filter
Examples of coating functional groups:
|Chlorine||Reactive grafting site|
|Thiol||Reactive grafting site|
|Quaternary amine||Reactive grafting site|
|Pentafluorophenyl esters||Reactive grafting site
Low surface energy