Identification and Validation of Analytical Chemistry Methods for Detecting Composite Surface Contamination and Moisture - Solid-State Electrochemical Sensor Study

In-field surface contamination and moisture detection is one of the critical issues in preparation of adhesive bonds between composite adherends for aircraft manufacture. In this paper, the feasibility of an all solid-sate electrochemical sensor technology is explored. Redox pairs or mediators are combined into a solid-state electrolyte, NafionTM. The output current in response to a cyclic polarization is used as the indication of the surface contamination level. Electrochemical impedance spectroscopy measurements using the sensors made were conducted. The results indicate that the small amount of moisture and/or sulfuric acid on initially cleaned and vacuumed polymer surfaces results in about 10 times increment of the peak current in cyclic voltammetry tests.