title: Interdigitated humidity sensors for a portable clinical microsystem.
abstract: This paper presents and compares two capacitive humidity sensors with interdigitated electrodes for a portable clinical application. A polyimide-sensitive layer covers the first structures and the optimized ones include a benzocyclobutene-sensitive layer and a heating resistor. Humidity measurements results are presented, in particular sensors response time in absorption, which are very small (inferior to 500 ms). Next, mechanisms of absorption and adsorption in a polymer layer are described and the two structures are compared. Suitability of optimized sensors for our application is discussed: new structures allow us to increase sensitivity and decrease response time. When the structure is maintained at 40 degrees C by its heater, the response time is 200 ms and the total desorption time is 11 s.
authors.affiliation: University of Bordeaux I, Laboratory IXL, Talence, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Laville
authors.forename: Claude
authors.initials: C
authors.lastname: Pellet
mesh_terms: D000327:Adsorption; D000535:Aluminum / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D025802:Electric Capacitance; D004867:Equipment Design; D004868:Equipment Failure; D006361:Heating; D006813:Humidity; D008839:Microelectrodes; D008904:Miniaturization; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D012117:Resins, Synthetic / Q000737:chemistry; D012680:Sensitivity and Specificity
chemical_list: D012117:Resins, Synthetic; C029945:polyimide resin; D000535:Aluminum