酸處理對聚二甲基矽氧烷表面親疏水性探討

Abstract

本文描述一個對聚二甲基矽氧烷的新化學表面改質方法。改質的結果利用水滴接觸角、掃描式電子顯微鏡、傅立葉紅外光譜儀等儀器來分析。而在剛硫酸處理後其接觸角由110°降到38°，其表面的甲基鍵結也被硫酸所打斷同時也把氫氧基嫁接上去。而酸處理後於空氣中靜置六個小時，表面也從原本的親水性轉變成疏水性。而上述的現象可以由兩個角度來解釋，酸處理的表面佈滿了微奈米級的小突起物，大大降低水滴與表面的接觸面積；另一個則是內部未受到酸處理的物質擴散到表面。此項結果的發現，無論是在親疏水產業或是微奈機電系統中皆有高度的利用性。

This paper describes a novel chemical modification of polydimethylsiloxane (PDMS) surface by using H2SO4 solution and subsequently the result of modification was confirmed by contact angle of water drops, Scanning Electric Microscope (SEM), and Fourier Transform Infrared spectrometry (FTIR). Soon after the acid treatment, the contact angle of the modified PDMS surface was reduced greatly from 110∘to 38∘owing to the H2SO4 solution destroyed the original bonding of the PDMS and the grafting of hydroxyl functional groups on the molecular chains of the PDMS surface. However, after six-hour of aging, the hydrophilic surface formed from acid treatments not only recovered to a hydrophobic one but also formed a super-hydrophobic exterior. This result can be explained from two aspects: one is by the discovery of the generation of micro-submicro-nano structure which is similar to the lotus leaf, and we considered that the air trapping in rough micro-nano binary structures can significantly decrease the contact area between water and the PDMS surface to increase the contact angle, the other one is the diffusion of lower molecular weight species from the inner bulk to the surface. Regarding to the importance of wettability and wide applications of PDMS, the potential technology for modulating the wettability of PDMS surface would be valuable in the applications of biosensors and nano-/micro-fabrication.