KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Wasapinyokul, KamolSubject: search.filters.subject.Annealing

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Effects of quenching process on the optical properties of thin film polymers
    (2019-07-01)
    Jumpar-Ngern, Jitrin
    ;
    Sompong, Khanisorn
    ;
    Wasapinyokul, Kamol
    Polymer is a group of materials applied in several thin film electronic devices. A typical fabrication process of the material consists of coating it as a film onto a substrate by a wet process, followed by the baking and annealing the film to change its molecular structures, and hence its properties. In this study, we reported the effect of the quenching process, or the cooling down process after baking, on the optical transmittance of the film. Thin films of poly(methyl methacrylate), or PMMA, was coated on a substrate and then baked at different temperatures followed by either a quick or slow cool-down quenching process; before they were checked for their optical transmittances. The results showed that the film baked at a temperature slightly higher than the glass transition temperature of the polymer, followed by a slow cool-down quenching process would provide the transmittance apparently lower than those of the films baking and quenching at other conditions. We believe that this was because when the polymer was baked above such temperature, the polymer was in its glassy state. When it was slowly cooled down, the molecules had time to form crystalline structure, hence a lower optical transmittance. The result from this study indicated that the quenching process can be used to control the properties of a polymer film and hence should be carefully practiced.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Modification of optical properties of spin-coated TiO2 film by heat treatments
    (2017-01-01)
    Chunarom, Chutinat
    ;
    Yontrarak, Tanapat
    ;
    Wipopcharoenkul, Puttinan
    ;
    Wasapinyokul, Kamol
    In this report, effects of heat treatment conditions on the transmittance of titanium dioxide, TiO<inf>2</inf>, films were examined. The colloidal solution of TiO<inf>2</inf> in two different solvents - isopropanol, IPA, and sulfuric acid, H<inf>2</inf>SO<inf>4</inf>, were deposited via a spin-coating method onto clean glass substrates. The films were subsequently annealed and cooled down, either quickly or slowly, before being measured for their optical transmittances in the visible region. Three points were noted: Firstly, when the films were quickly cooled down after annealed, their transmittance depended on their annealing temperature. In IPA and H<inf>2</inf>SO<inf>4</inf>, the transmittance decreased and increased, respectively, when the annealing temperature increased. Secondly, when the films were slowly cooled down after annealed, their transmittance seemed to be independent from the annealing temperature, where the films had roughly equal transmittance regardless of annealing temperature. Lastly, the TiO<inf>2</inf> films with H<inf>2</inf>SO<inf>4</inf> provided higher transmittance than those with IPA. All the three stated characteristics were the same for all wavelengths in the visible region. These results were believed to result from the dispersibility of the TiO<inf>2</inf> in each solvent and the cooling-down processes. Such results could be further developed to select a suitable heat treatment process for a spin-coated TiO<inf>2</inf> film with a desired optical transmittance.