Ca Carboxylate Formation at the Calcium/Poly(methyl methacrylate) Interface

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• 作者：Huanxin Ju ; Xuefei Feng ; Yifan Ye ; Liang Zhang ; Haibin Pan ; Charles T. Campbell ; Junfa Zhu
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：September 27, 2012
• 年：2012
• 卷：116
• 期：38
• 页码：20465-20471
• 全文大小：478K
• 年卷期：v.116,no.38(September 27, 2012)
• ISSN：1932-7455

文摘

Chemical reactions occurring at the interface during the growth of Ca films on poly(methyl methacrylate) (PMMA) by vapor deposition at room temperature have been investigated in detail by X-ray photoemission spectroscopy (XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The changes of the O 1s, C 1s, and Ca 2p core level XP spectra upon Ca deposition directly indicate that Ca atoms preferentially react with the ester groups of PMMA at very low coverages, leading to the formation of polymeric Ca carboxylate and loss of methyl groups. The O K-edge NEXAFS spectra further confirm that the ester groups of the PMMA are the primary active sites for reaction with Ca atoms. The results of XPS and NEXAFS measurements are fully consistent with those from adsorption microcalorimetry studies reported in our previous work. Therefore, the reaction mechanism between Ca and PMMA has confirmed that Ca atoms react with the ester groups in PMMA to form polymeric Ca carboxylate in the early stages of Ca adsorption.