The Influence of Deposition Solution pH and Ionic Strength on the Quality of Poly(N-isopropylacrylamide) Microgel-Based Thin Films and Etalons
The Influence of Deposition Solution pH and Ionic Strength on the Quality of Poly(N-isopropylacrylamide) Microgel-Based Thin Films and Etalons
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DOI：
10.1021/am403745k
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发表时间：
2013-11-27
影响因子：
9.5
通讯作者：
Serpe, Michael J.
中科院分区：
文献类型：
--
作者：
Hu, Liang;Serpe, Michael J.
通过在Au涂覆的基底上“涂敷”pNIPAm-co-AAc微凝胶单层，然后沉积另一层Au覆盖层，制备了基于聚（N-异丙基丙烯酰胺）-co-丙烯酸（pNIPAm-co-AAc）微凝胶的薄膜和标准具。在此，原位观察pH和离子强度（I.S.）影响微凝胶沉积，并最终进行标准具的光学均匀性和pH敏感性。结果表明，微凝胶紧密地包装在Au衬底上时，他们在pH 3.0沉积，导致良好的光学均匀性。此外，增加涂料溶液I.S.导致微凝胶在基底上的堆积密度略微降低，但增强了微凝胶层溶胀的能力，当浸入pH 3.0的溶液中时显示出较厚的聚合物层。当在pH 7.5下涂漆时，标准具的光学均匀性以溶胀性、夸大的高I. S.我们还确定了该装置对pH变化的灵敏度，并发现当微凝胶在pH 7.5下沉积时具有最大灵敏度。10 MM。
Poly(N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgel-based thin films and etalons were fabricated via "painting" a pNIPAm-co-AAc microgel monolayer on a Au-coated substrate, followed by the deposition of another Au overlayer. Herein, in situ observation of how the pH and ionic strength (I.S.) of the painting solution influenced microgel deposition and, ultimately, the optical homogeneity and pH sensitivity of the etalon was carried out. It was shown that microgels closely pack on the Au substrate when they are deposited at pH 3.0, leading to a good optical homogeneity. Additionally, increasing the painting solution I.S. leads to a slight decrease in microgel packing density on the substrate, but enhances the ability of the microgel layer to swell, exhibiting thicker polymer layers when immersed in pH 3.0 solutions. When painting at pH 7.5, the optical homogeneity of the etalon is improved at the expense of swellability, exaggerated high I.S. We also determined the device's sensitivity to pH changes and found a maximum sensitivity when the microgels were deposited at pH 7.5 with an I.S. of 10 mM.