...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, B. Condensed matter, materials, surfaces, interfaces & biophysical >Measurement of Infrared Molar Absorptivity of a Surfactant Adsorbed onto a Solid Substrate over a Wide Range of Surface Concentrations Using Octadecyltrichlorosilane Langmuir-Blodgett Transferred Films
【24h】

Measurement of Infrared Molar Absorptivity of a Surfactant Adsorbed onto a Solid Substrate over a Wide Range of Surface Concentrations Using Octadecyltrichlorosilane Langmuir-Blodgett Transferred Films

机译：使用十八烷基三氯硅烷Langmuir-Blodgett转移膜在宽范围的表面浓度下测量表面活性剂吸附在表面上的红外吸收率

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

For the first time, we measure the molar absorptivity (in the infrared range) of a surfactant species adsorbed onto a solid substrate, ε↓（ads）. With this measurement, infrared methods can be used to determine the surface coverage of a surfactant adsorbed at an interface. In particular, the absorptivity is measured for the asymmetric -CH- stretch of the -CH↓(2)- moiety in the adsorbed molecules using octadecyltrichlorosilane (OTS) as the model species. A monolayer of OTS is spread onto the air/water interface of a Langmuir balance and compressed to a predetermined surface coverage. The film is then transferred onto the native silicon oxide layer of a silicon substrate using the Langmuir-Blodgett transfer technique, using a transfer ratio of approximately 1, so that the transferred layer's surface coverage is equal to the known coverage of the Langmuir monolayer. The infrared spectra of the transferred films are measured, and the molar absorptivity is calculated for the methylene asymmetric stretch in the region of 2920 cm↑(-1) The ε↓(ads) is found to be independent of surface coverage for the monolayers transferred in the LE, LC, and LE-LC coexistence phases. This absorptivity was found to be 1.7 × 106 cra/mol of -CH↓(2)- , which is nearly 50% larger than our measured value of the molar absorptivity of the same species in bulk. The absorptivity was found to be dependent on the surface coverage in the LS state. The accurate determination of the surface coverage at the air/water interface necessitates minimizing the polymerization of OTS both at the air/water interface and in the spreading solution. We report a set of parameters for this minimization.
机译：首次，我们测量了吸附在固体基质上的表面活性剂物质ε↓（ads）的摩尔吸收率（在红外范围内）。通过这种测量，可以使用红外法确定吸附在界面上的表面活性剂的表面覆盖率。特别地，使用十八烷基三氯硅烷（OTS）作为模型物质，测量吸附分子中-CH↓（2）-部分的不对称-CH-延伸率。将单层OTS散布到Langmuir天平的空气/水界面上，并压缩到预定的表面覆盖率。然后使用Langmuir-Blodgett转移技术，以大约1的转移比率，将薄膜转移到硅基底的天然氧化硅层上，这样转移的层的表面覆盖率等于Langmuir单层的已知覆盖率。测量转移膜的红外光谱，并计算2920 cm↑（-1）区域中亚甲基不对称拉伸的摩尔吸收率。发现ε↓（ads）与转移的单层表面覆盖率无关在LE，LC和LE-LC共存阶段。发现该吸光度为-CH↓（2）-的1.7×106 cra / mol，比我们对相同物种散装的摩尔吸光度的测量值大将近50％。发现吸收率取决于LS状态下的表面覆盖率。在空气/水界面处的表面覆盖率的准确确定使得在空气/水界面处和铺展溶液中OTS的聚合最小化是必要的。我们报告了用于最小化的一组参数。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号