A capacitance sensor for on-line monitoring of ultrathin polymeric film growth

摘要

An interdigitated metallic electrode array fabricated using standard photolithography and wet-etching techniques, is applied as a capacitance sensor. A theoretical model is developed which predicts a sensitivity of approximately 2 fF/monomolecular layer, well within the detection capability of modern digital bridges. Experimental data from Langmuir/Blodgett depositions of organic and polymeric films accurately confirm the theoretical predictions. The sensors have also provided the first real-time measurements of water exclusion from such films.