奈米纖維薄膜覆蓋微米柱陣列表面之抗冰與除冰能力

Abstract

冰的累積會影響許多工業系統，也會造成許多經濟上的困擾及生活中的危害，冰的形成大部分主要為結冰(氣態變為液態再轉為固態)。目前大多抗冰研究表明超疏水表面具有抵抗結冰的效果，關於親水表面的研究較少，由於尼龍六奈米纖維具有重量輕、低成本、及吸水性等特性，本研究提出一結合微米柱陣列與尼龍六奈米纖維薄膜之抗冰表面，此微米柱陣列結合尼龍六奈米纖維薄膜表面可藉由尼龍六薄膜將冰限制在薄膜內而避免表面形成 Wenzel 型式的冰，且微米柱陣列可將奈米纖維薄膜撐起，以此降低熱傳面積，並減少冰的附著力。 本研究首先量測平面矽表面、微米柱陣列表面、與微米柱陣列結合尼龍六奈米纖維薄膜表面之結冰時之熱傳係數，結果顯示，微米柱陣列結合尼龍六奈米纖維薄膜表面具有最低的熱傳係數，此或許是因為尼龍六吸水性將水控制在纖維膜內，使冰以 Cassie 型態附著在表面上，提高整體熱阻也許能抑制冰層的成長，使得表面具有較薄的冰層，達到有效抗冰能力；此外，由於冰在平面矽表面具有良好的接觸，因此平面矽表面有最高的熱傳係數，而微米柱陣列表面的熱傳係數居於兩表面中間。 冰粘附應力是評價表面除冰性能的指標，實驗結果顯示，微米柱陣列結合尼龍六奈米纖維薄膜表面相比於矽表面能大幅度的降低冰冰粘附應力，綜合上述結果，微米柱陣列結合尼龍六奈米纖維薄膜表面有良好的抗冰能力與除冰能力。

Ice accumulation affects industrial systems’ operations and may cause economic and life-threatening problems. Most ice formation processes are freezing, which involves the phase transitions from gas to liquid and from liquid to solid. Research on anti-icing indicates that superhydrophobic surfaces have the effect of resisting icing.Nevertheless, less attention has been paid to applying hydrophilic surfaces to resist ice.Nylon-6 nanofiber membranes have the characteristics of low-cost, lightweight, and water-absorbing properties and may be a potential surface applicable for anti-icing. Therefore, a micropillar array coated with the nylon-6 nanofiber membrane was proposed as an anti-icing surface in this study. The nylon-6 nanofiber membrane absorbs the water liquid and can potentially prevent the formation of Wenzel ice on the surface. In the meantime, the micropillar array supports the nanofiber membrane and can also reduce the heat transfer area and decrease the ice adhesion. The anti-icing performances on a plain Si surface, a micropillar array surface, and the micropillar array coated with the nylon-6 nanofiber membrane were examined. The results show that the micropillar array coated with the nylon-6 nanofiber membrane had the lowest heat transfer coefficient. This might be due to the water-absorbing nylon-6 membrane keeping the water inside the membrane and causing the formation of Cassie ice on the surface. On the other hand, the ice on the plain Si surface had better contact, and therefore the plain Si surface had the highest heat transfer coefficient among the surfaces, and the micropillar array gave a heat transfer coefficient between the two surfaces. The large thermal resistance of the micropillar array coated with the nylon-6 nanofiber membrane inhibits the growth of the ice layer, resulting in a thin ice layer on the surface and giving an effective anti-icing capability. Ice adhesion stress is an indicator for evaluating the deicing property of a surface. A lower ice adhesion stress leads to better deicing performance. The experimental results show that the micropillar array coated with the nylon-6 nanofiber membrane surface significantly reduced the ice adhesion stress from the plain Si surface. Consequently, the micropillar array coated with the nylon-6 membrane surface showed superior anti-icing and deicing capabilities.