| Popis: |
It is generally known that the water molecules from air can be easily absorbed and/or permeate into the materials and influence their physical properties. Therefore, the growing need for accurate quantification and controlling of relative humidity has led to tremendous attention and rise in the researches on humidity sensors. Comparing the basic working principles, humidity sensors can be divided into two categories, reversible and irreversible humidity sensors. The irreversible humidity sensors offer a simple means to detect moisture and record exposure history when more complex dedicated continuous monitoring is not feasible, such as in confined spaces. The focus of this study is mainly on the designing of polymeric latent humidity sensor showing a distinguishable permanent change by humidity exposure. The primary sensing approach and mechanism exploits the amphiphilic block copolymer tin film nanodomain formation (islands and holes) when the thin films are exposed to water vapor chosen to selectively swell a given block component and the surface reorganization develops after exceeding specific threshold relative humidity. Firstly, the cationic quaternary ammonium polymers were chosen as desirable primary active humidity sensing material and investigated for the detailed analysis on the effects of moisture on the glass transition temperature of cationic quaternary ammonium polymers. Secondly, the amphiphilic block copolymers containing cationic quaternary ammonium polymers were spun coated as thin film, and investigated the moisture-induced morphological transition on film surface for irreversible humidity sensing applications. |
