Study on flow and structure change on drawing and drying process for production of functional thin film

本研究主要研究了液晶溶液的应用和干燥过程。在玻璃板上受剪切变形取向的液晶溶液薄膜具有光学各向异性。使用这种工艺，二向色或双折射薄膜和太阳能电池板的生产将比目前的工艺更容易，制造成本将降低。为此研制了一种固定平板玻璃并使其匀速滑动的镀膜装置。在有1 ~ 10□m薄间隙的玻璃板上设置涂抹器。将预定量的样品液滴加在玻璃板上，并用涂布器涂刷。涂在玻璃上的液体薄膜经自然调味而成薄膜。用偏光显微镜观察干燥过程，用激光位移传感器测量液膜厚度的变化。用偏振法测量了薄膜的光学各向异性，如二色性和双折射性。在液膜干燥过程中，膜厚的减少速度不是恒定的，并以恒定的频率振动。这与本研究观察到的干燥过程中液体微流动运动的发生有关。该薄膜表现出强烈的二色性，但它包含带织构，降低了光学薄膜的质量。在所有实验条件下，都产生了条带织构。涂膜速度和涂膜器间隙对薄膜质量没有影响

In this study, the thin film formation process by application and drying of chromonic liquid crystal solution was investigated. The thin film of chromonic liquid crystal solution which is oriented by shear deformation on a glass plate has optical anisotropy. Using this process, dichroic or birefringence films and solar battery panels would be produced easier than their current processes, and manufacturing cost would be reduced. The coating device which holds a flat glass plate and slides it with a constant velocity was made for this investigation. An applicator is set up the glass plate with thin gap which is 1 to 10 □m. The predetermined amount of the sample liquid is added dropwise on the glass plate, and it is painted with the applicator. The painted thin liquid film on the glass becomes thin film by natural seasoning. The process of drying is observed by polarized microscope and the decreasing thickness of the liquid film is measured by laser displacement sensor. The optical anisotropy, such as dichroism and birefringence, of the thin film is measured by polarimetry technique. In the liquid film drying, the reduction velocity of the film thickness is not constant and vibrates with a constant frequency. It is related to occurrence of the micro flow motion of the liquid by drying which was observed in this study. The thin film exhibits strong dichroism but it includes the band-texture which reduces the quality of the optical film. At all experimental conditions, the band-texture was generated. The coating speed and the gap of the applicator did not influence the quality of the thin film