Thin-film diaphragms of cellulose nanofiber fabricated using high-concentration polar dispersion for application to MEMS actuators
Thin-film diaphragms of cellulose nanofiber fabricated using high-concentration polar dispersion for application to MEMS actuators
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DOI：
10.1016/j.sna.2019.01.007
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发表时间：
2019-04
期刊：
影响因子：
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通讯作者：
S. Imai
中科院分区：
文献类型：
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作者：
S. Imai
提出了一种用于MEMS驱动器或微流控器件位移膜的纤维素薄膜膜片（CNF）的制备方法，并对其力学性能进行了评价。CNF具有高强度和弹性模量;然而，需要提供用作置换膜的柔性。使用约66体积%的高浓度的极性溶剂叔丁醇（tBA）来使CNF膜变薄，即，降低CNF的聚集和粘度。用该方法制备的CNF薄膜厚度约为4 μm。制备的薄膜具有良好的气体阻隔性能，并具有各向同性的杨氏模量。在CNF膜的表面上沉积铝蒸发层（约t0.3 μm）作为防水性的屏蔽层。在气压或磁场作用下测量了薄膜膜片的位移特性（t4 μm），结果与厚度为7.5 μm的聚酰亚胺薄膜的位移特性接近。保证了位移的动态再现性和回弹性。所提出的方法可以很容易地形成CNF薄膜的厚度下降到几个微米，所制造的薄膜可以用作气体和液体的位移膜。
A method of fabricating thin-film diaphragms of cellulose nanofiber (CNF) for the application of displacement membranes of MEMS actuators or microfluidic devices was developed and the mechanical characteristics were evaluated. CNF has high strength and elastic modulus; however, it is necessary to provide flexibility for the use as a displacement membrane. A polar solvent, tertiary-butyl alcohol (tBA), at a high concentration of approximately 66 vol%, was used to thin the CNF film, that is, to reduce the aggregation and viscosity of the CNF. The CNF films fabricated by this method were of approximately 4-μm thickness. The fabricated films had a good gas barrier property and had an isotropic Young's modulus. An evaporation layer of aluminum (approximately t0.3 μm) was deposited on the surface of the CNF film as a shield layer for water repellency. The displacement characteristics of the diaphragm of the film (t4 μm) were measured in the actuators using air pressure or a magnetic field and they were close to those of a polyimide thin film of thickness 7.5 μm. The dynamic reproducibility and resilience of the displacement were ensured. The proposed method could easily form CNF films of thickness down to several micrometers and the fabricated films could be used as displacement membranes for gases and liquids.