Hegewald Jan, Schmidt Thomas, Eichhorn Klaus-Jochen, Kretschmer Katja, Kuckling Dirk, Arndt Karl-Friedrich
Institut für Physikalische Chemie und Elektrochemie, Technische Universität Dresden, Mommsenstr. 13, D-01062 Dresden, Germany.
Langmuir. 2006 May 23;22(11):5152-9. doi: 10.1021/la053461c.
Temperature-sensitive hydrogel films were synthesized by electron beam irradiation of poly(vinyl methyl ether) (PVME) on silicon (Si/SiO(2)) substrates and gold (Au) coated glass slides. The temperature-dependent swelling behavior of the films in aqueous solution was characterized by in situ spectroscopic ellipsometry and a combination of surface plasmon resonance (SPR) and optical waveguide spectroscopy (OWS). The results of both techniques are compared. The suitability of both techniques for the characterization of the swelling behavior of thin hydrogel films is demonstrated. The volume swelling degree in the swollen state decreases with increasing radiation dose D. This is explained by the fact that the number of formed polymeric radicals, and hence cross-linking density, increases with D. Above the phase-transition temperature, the swelling degrees were independent of D, slightly above 1. The swelling/deswelling process was fully reversible and is mainly directed perpendicular to the substrate surface. The phase-transition temperature was determined to be T(cr) approximately 33 degrees C. However, T(cr) slightly decreases with increasing D and increasing film thickness d.
通过在硅（Si/SiO₂）衬底和金（Au）涂层载玻片上对聚（乙烯基甲醚）（PVME）进行电子束辐照，合成了温度敏感水凝胶薄膜。通过原位光谱椭偏仪以及表面等离子体共振（SPR）和光波导光谱（OWS）的组合，对薄膜在水溶液中随温度变化的溶胀行为进行了表征。比较了这两种技术的结果。证明了这两种技术用于表征薄水凝胶薄膜溶胀行为的适用性。溶胀状态下的体积溶胀度随辐射剂量D的增加而降低。这可以通过以下事实来解释：形成的聚合物自由基数量以及交联密度随D增加。在相变温度以上，溶胀度与D无关，略高于1。溶胀/去溶胀过程是完全可逆的，并且主要垂直于衬底表面进行。确定相变温度为T(cr)约33℃。然而，T(cr)随D的增加和薄膜厚度d的增加而略有降低。
