可撓式石墨烯高分子軟性導電薄膜加熱器之開發應用於滾壓與曲板壓印製程之探討

Development of Rolling and Curved Surface Hot Embossing System Using Ultra-thin Flexible Electronic Heating Elements of Graphene Polymeric Composite in Polymeric Components Fabrication

柯坤呈(Kun-Cheng Ke)

指導教授 ： 楊申語

國立臺灣大學/工學院/機械工程學研究所/博士(2018年)

https://doi.org/10.6342/NTU201803675

摘要

高分子壓印製程面臨升溫太慢與溫度不均之問題，如何提升升溫速率與改善溫度均勻性成為亟需克服之挑戰。本研究利用具有優良導電性、導熱性及機械性質的石墨烯複合材料開發可撓曲大面積加熱薄膜並應用於曲面微熱壓與微熱滾壓製程。
首先，探討不同膠體對分散性、電阻與片電阻之影響與可撓式測試，確立可撓式加熱器效能之可行性。接著應用可撓式加熱器開發石墨烯複合材料平板加熱器，探討其電流走向趨勢、邊界效應與電熱性質。實驗數據證明找出供給電壓、塗佈面積與升溫速率、穩態溫度之間的關係，結果顯示隨著電壓的升高，升溫速率與穩態溫度皆會提升。
本研究利用加熱器的高度可撓性，將其應用於曲面壓印製程，25V電壓驅動加熱器，於130秒內溫度由40℃提升至160℃。將此加熱器用於曲面基材上，輔以氣體施壓以進行曲面壓印；成型之結果顯示，V型結構複製率達到97%以上。顯示本實驗架構下可有效於曲面下複製表面微結構。
本研究更進一步將石墨烯複材加熱器應用於滾壓成型，開發滾筒可撓式加熱器，設計滾筒內部貼附開發完成加熱器，藉由調整電壓測試其滾筒式電熱性質、四方位動態溫度均勻性、橫向動態升溫均勻性與穩態溫度與電壓之關係。四方位動態升溫控制其溫度於2.8℃內，橫向動態溫度結果控制於1.2℃ 以內。
本研究亦將可撓式加熱器應用於微熱滾壓製作微透鏡陣列結構，探討壓力、工作溫度與進給速度對成型之關係。固定進給速度參數下，微透鏡陣列高度與直徑成型皆超過原模具尺寸。接著，複製V型結構，壓印參數固定在120℃，其成型結果更能達到98%之複製率。V型結構有效增強光強度。本研究證實石墨烯複合材料可撓式加熱器用於曲面與滾筒壓印的可行性與潛力。

關鍵字

可撓性 ； 石墨烯複材 ； 軟性電子 ； 薄膜加熱器 ； 微熱滾壓 ； 曲面板壓印

並列摘要

The polymer process faces the problems of slow temperature rise and uneven temperature. Increasing the heating rate and improving the temperature uniformity become an urgent challenge. In this study, a flexible large-area graphene-composite heating film was developed .The heating films were then applied to the processes of curved micro-hot embossing and micro-hot rolling embossing.
First, the effects of different colloids on dispersibility, resistance, sheet resistance and flexible testing were investigated to determine the feasibility of flexible flexible heaters. Then, a flexible graphene composite flat panel heater was developed. The results show that as the voltage increases, the heating rate and steady-state temperature increases.
The flexible heater was used to the hot embossing on the curved substrate. With the power of 25V, the temperature was raised from 40 ° C to 160 ° C in 130s. Stable temperature can be maintained. The V-shaped microstructures are replicated with replication rate higher than 97%.
A roller heater was developed for roller hot embossing. The heater was fabricated by wire bar coating of graphene polymer composite onto the inner wall of the hollow roller. The electrothermal property, the four-quadrant dynamic temperature uniformity, the lateral dynamic temperature uniformity and the steady-state temperature and voltage are tested by adjusting the voltage. The four-quadrant dynamic temperature control temperature is controlled within 2.8 °C, and the lateral dynamic temperature result is controlled within 1.2 °C.
The roller heater was used in micro-hot roller embossing to fabricate microlens array and V-type structures. The relationship between pressure, working temperature and feed rate on forming were investagated. Under the fixed feed rate parameter, the height and diameter of the microlens array were all larger than original sizes of the mold. The V-shaped structure is formed at the fixed rolling speed rate parameter. With the embossing temperature fixed at 120 ° C, the replication rate were higher than 97%. Finally, the application of V-type structure to light intensity enhancement was verified. This study proved the feasibility and potential of the graphene polymer composite heater successfully.

並列關鍵字

flexibility ； graphene composite ； flexible electronic ； thin film heater ； curved micro-hot embossing ； micro-hot rolling embossing

參考文獻

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