Department of Material Science and Engineering, University of Florida, Box 116400, Gainesville, Florida 32611, USA.
ACS Appl Mater Interfaces. 2013 Feb;5(4):1218-25. doi: 10.1021/am301967v. Epub 2013 Feb 12.
X-ray photoelectron spectroscopy (XPS) and static contact angle measurements were used to study the interaction between silane coupling agents and cured cement paste. Three different silane coupling agents were investigated: aminopropyltriethoxy silane (APTES), 3-glycidyloxypropyltrimethoxy silane (GPTMS), and methoxy-terminated polydimethxyl siloxane (PDMS). These silanes have different end groups, so the change in surface energy after undergoing a successful reaction between the silane and hydroxyls on the surface of the cement paste was demonstrated by a change in contact angle. Relative to untreated samples, APTES samples decreased the contact angle, PDMS samples increased the contact angle, and GPTMS did not show a significant change in contact angle. Samples with a water-to-cement ratio (w/c) of 0.5 showed a larger change in contact angle than 0.4 w/c ratio samples, because of a greater number of hydroxyl groups at the surface. Deconvolution of the O 1s and Si 2p XPS peaks were performed to determine contributions from bridging and nonbridging atoms. An increase in bridging silicon and oxygen atoms relative to untreated samples indicated successful silane condensation and that a covalent bond was formed between the cement paste and silanes.
X 射线光电子能谱（XPS）和静态接触角测量用于研究硅烷偶联剂与固化水泥浆之间的相互作用。研究了三种不同的硅烷偶联剂：氨丙基三乙氧基硅烷（APTES）、3-缩水甘油丙基三甲氧基硅烷（GPTMS）和甲氧基封端的聚二甲基硅氧烷（PDMS）。这些硅烷具有不同的端基，因此通过接触角的变化证明了硅烷与水泥浆表面的羟基之间成功反应后表面能的变化。与未处理的样品相比，APTES 样品降低了接触角，PDMS 样品增加了接触角，GPTMS 样品接触角没有明显变化。水灰比（w/c）为 0.5 的样品比 0.4 w/c 比样品的接触角变化更大，因为表面的羟基数量更多。对 O 1s 和 Si 2p XPS 峰进行了分峰处理，以确定桥接和非桥接原子的贡献。与未处理的样品相比，桥接硅和氧原子的增加表明硅烷缩合成功，并且水泥浆与硅烷之间形成了共价键。
