| Summary: | 博士 === 大同大學 === 材料工程學系(所) === 99 === Because of technology improvement and life convenience, people begin to require better life quality and security. When living is getting more convenient, people commence to figure out how to improve life quality; therefore, there are some technical developments of alert and protection products. The plasma deposition and surface grafting polymerization have been used to modify the surface structure and properties of inorganic substrates such as organic nature, structural constitution, hydrophilicity, functional groups, and conductivity. The first part of the fabricating the humidity sensitive layer, the monomeric solution of organic electrolyte NaSS had been spin-coated on the designed electrodes with different patterns, then exposed to UV-light to induce grafting polymerization. The second part of tin oxide (SnOx) organic-like thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) of tetramethyltin (TMT) and O2 gas mixtures at low temperature. The organic-like thin films containing peroxides or free radicals can be subsequently grafted hydrophilic polymer by UV-induced grafting polymerization or spin coating poly ethylene glycol (PEG) on substrate.
In this study, humidity sensitive polymer layer containing phenol-formaldehyde resin is prepared by spinning coating on the comb-shape type electrode, then followed by UV-graft polymerization of water soluble monomer which was performed to make water-resistive and the sensitive humidity sensor.
In the first part of this study, two types of sensors were developed. The first one was treated with Hexamethyldisilazan (HMDSZ)-plasma and followed by grafting polymerization of NaSS using UV-light and adding different ratio of phenol-formaldehyde resin. This type of sensor has linear response with %RH and high sensitivity (impedance from 106 Ωto 103Ω). The second type of sensor was treated with isopropanol (IPA)-plasma and then grafting polymerization of AAc by UV-light. Also have impedance linear response with %RH, impedance various from 107 Ω to 105Ω.
In the second part of this study, surrounding environment, carbon monoxide is often produced as exhaust gas from cars, factory flues, coal, or fuel gas. When an excessive amount of carbon monoxide is inhaled into a human body, it will decrease the oxygen carrying efficiency of hemoglobin. When a human body is exposed to a high concentration of carbon monoxide situation, the cerebrum will lose its normal function and even death may follow. Furthermore, since carbon monoxide possesses the characteristics of lacking color, taste, and stimulus, people cannot detect any danger through their own senses. Therefore, the detection technology of the carbon monoxide detector is particularly important in the present living environment. Post treatment on a new room temperature type gas sensor device based on the organically hybridized plasma deposition of tetramethyltin (TMT) films was developed to detect and distinguish the presence of methane, butane, and carbon monoxide in the test environment. Plasma-deposited thin films were first prepared from TMT and O2 gas mixtures to obtain SnOx thin films at room temperature. Post treatments on the SnOx thin films by (1) spin coating poly ethylene glycol (PEG), or (2) surface grafting acrylamide (AAm) or p-styrenesulfonic acid sodium salt (Nass) were then performed. Higher proportion of TMT in the TMT/O2 mixture tends to increase organic nature of the deposited films and exhibit surface hydrophobic property. Post treatment by spin coating with PEG shows smooth linear response to CO gas, and their sensitivities are not affected by methane or butane gas. The change of sensor resistance can be detected without heating with change in CO concentration from 30 ppm to 650 ppm. Detection experiments with the test modules used to smoldering the development and utilization of a candle burning incomplete combustion of poorly ventilated environment detection CO concentration in the establishment of a ≧ 50ppm, flash warning, CO concentration ≧ 100ppm, sound alerts, CO concentration ≧ 200ppm, given the high volume sound alerts. Used in industrial safety and environmental design in addition to the gas sensor sensitivity, selectivity, response time than should also consider portability, power consumption and other factors, so by quartz crystal microbalance (QCM), QCM sensor is operation easy, simple principles, rapid response and other characteristics, the oscillation frequency will be adsorption of changes in mass. For being widely used and reversible, selective film can be produced on inorganic surface layer of sensor. Tin oxide (SnOx) organic-like thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) of tetramethyltin (TMT) and O2 gas mixtures at low temperature. The organic-like thin films containing peroxides or free radicals can be subsequently hydrophilic polymer PEG by spin coating. The sensor can be used in detecting environment which is smoldering. This film can transform to adsorption state and changes QCM frequency which can be signal to sensor rings.
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