三硅醇苯基多面体低聚倍半硅氧烷的朗缪尔-布洛杰特膜中甲基膦酸二甲酯的吸附作用

Sorption of dimethyl methylphosphonate within Langmuir-Blodgett films of trisilanolphenyl polyhedral oligomeric silsesquioxane.

作者信息

Ferguson-McPherson Melinda K, Low Emily R, Esker Alan R, Morris John R

机构信息

Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.

出版信息

J Phys Chem B. 2005 Oct 13;109(40):18914-20. doi: 10.1021/jp0521959.

DOI:10.1021/jp0521959

PMID:16853435

Abstract

Trisilanolphenyl polyhedral oligomeric silsesquioxane (POSS) molecules are used to create well-ordered Langmuir-Blodgett films containing silanol groups that interact strongly with dimethyl methylphosphonate (DMMP), a commonly used simulant for the chemical warfare agent sarin. The interaction of DMMP within multilayer POSS films is studied by uptake coefficient and temperature-programmed desorption (TPD) measurements, as well as reflection-absorption infrared spectroscopy (RAIRS). Results indicate a low uptake probability; however, in a DMMP-saturated atmosphere, the organophosphonate molecules are capable of diffusing into and adsorbing within the films. TPD and RAIRS measurements reveal no evidence of DMMP decomposition within the film. Rather, DMMP is found to desorb molecularly with a desorption energy of 122 kJ/mol. RAIRS reveals that strong hydrogen-bonding interactions between the phosphoryl groups of the organophosphonate molecules and the silanol groups of the POSS molecules are responsible for the high sorption energy of the system.

摘要

三硅醇苯基多面体低聚倍半硅氧烷（POSS）分子用于制备含有硅醇基团的有序朗缪尔-布洛杰特膜，这些硅醇基团与二甲基甲基膦酸酯（DMMP）强烈相互作用，DMMP是化学战剂沙林的常用模拟物。通过摄取系数、程序升温脱附（TPD）测量以及反射吸收红外光谱（RAIRS）研究了多层POSS膜中DMMP的相互作用。结果表明摄取概率较低；然而，在DMMP饱和气氛中，有机膦酸酯分子能够扩散到膜中并吸附在膜内。TPD和RAIRS测量没有发现膜内DMMP分解的证据。相反，发现DMMP以122 kJ/mol的脱附能量分子解吸。RAIRS表明，有机膦酸酯分子的磷酰基与POSS分子的硅醇基团之间的强氢键相互作用是该系统高吸附能的原因。