石墨烯複材加熱器應用於軟滾輪熱壓印製程

Application of Graphene-polymer Composite Heaters in Soft Roller Hot Embossing Process

呂昀庭(Yun-Ting Lu)

指導教授 ： 蔡曜陽

共同指導教授 ： 楊申語(Sen-Yeu Yang)

國立臺灣大學/工學院/機械工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201702870

摘要

滾輪熱壓印可連續複製微結構，但由於傳統使用電熱盤加熱耗時，導致製程時間過長而限制產量。本研究開發可撓曲的大面積快速加熱薄膜來加熱，選用具有優良導電性、導熱性及機械性質的石墨烯複合材料來製作加熱薄膜。
　　本研究首先製作115115 mm之石墨烯複材薄膜於PI膜上，以85 V電壓，67秒即可使加熱溫度達到180 ℃。將加熱器連續重複彎曲5000次，由電阻變化觀察出其電阻僅有微小變動，表示其材料亦可應用於可撓性加熱器。
　　本研究接著利用大面積熱壓成型，再經PDMS微鑄造技術，將直徑54.88 μm、高度8.096 μm、間距99.42 μm的球面微透鏡凹穴陣列，製作在環形PDMS軟模的外圍。當施加壓力於滾輪軸上時，PDMS軟模與基材間為面接觸，利用感壓軟片實驗，證實不同滾壓速度滾壓壓力都均勻。
　　本研究設計製造滾輪微熱壓機台，整合石墨烯複材薄膜加熱器、環形軟模具、施壓組件、移動平台，並使用此石墨烯複材加熱器應用於軟滾輪壓印，成功壓印出微透鏡陣列，並試以不同壓印溫度及壓印壓力作為結構複製壓印參數，找出成型視窗，將壓印成品劃分成九個區域，達到全面積轉寫率大於92.9 %之成果，證明石墨烯複材加熱器應用於軟滾輪熱壓印製程的可能性。

關鍵字

石墨烯複合材料 ； 薄膜加熱器 ； 熱壓印 ； 滾輪壓印 ； 微結構

並列摘要

In recent years, roller hot embossing has been considered as the most efficient technique for replicating microstructures onto polymeric substrate. How to heat up the substrate before roller-embossing is always challenging. The first purpose of this study is to develop a large-area film heater by using the graphene–polymer composite. The thermal and electrical conductivity, along with mechanical strength, make graphene-polymer composite an excellent film heater. The graphene-polymer composite heaters, with an area of 115  115 〖"mm" 〗^"2" , is made of a 8.05 μm thick coating layer of graphene–polymer composite on PI film. It can heat up to 180℃ within 67s with a voltage of 85 V. The bending fatigue test showed that the graphene-based heater can withstand over 5,000 bending cycles.
The second purpose of this study is to increase the contact area and to ensure the conformity of the contact between the mold and the substrate. For this purpose, a soft mold is used. The soft mold is made with hot embossing and PDMS casting with the microlens array on the surface. The dimensions of the microlens array are 54.88 μm in diameter, 8.906 μm in height and 99.42 μm in pitch. The uniform pressure distribution on the substrate has been proved using pressure sensitive films.
With this graphene-polymer composite heater and soft PDMS roller mold, along with pneumatic cylinder and movable platform, a roller hot embossing apparatus is designed and implemented. The embossing pressure and temperature are main parameters during the roller hot embossing process. Operation window, within which the microlens array can be successfully fabricated, was investigated. Over 92.9% of replication rate can be achieved. This study demonstrates the potential of this graphene–polymer composite heating soft roller hot embossing for efficient fabrication of microstructures on polymeric substrates.

並列關鍵字

graphene–polymer composite ； film heater ； hot embossing ； roller embossing ； microstructure

參考文獻

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