首页> 外文学位 >文献详情
【6h】

Surfactant aggregate morphology on surfaces: Insights from molecular simulations.

机译:表面活性剂聚集体的表面形态:分子模拟的见解。

获取原文
获取原文并翻译 | 示例
¥30

摘要

Surfactants are an important class of molecules used in number of applications at a range of length scales. Oil recovery, mineral recovery, detergency are applications that have been using surfactants for decades, whereas colloidal dispersions of nanoparticles, preparation of nano-porous materials, dispersing carbon nanotubes are new applications of surfactants that are currently gaining prominence. The aggregate structure of surfactants plays an important role in determining the structure of nanoporous materials, ability of surfactants to disperse colloidal particles, carbon nanotubes and graphene nanosheets. To better understand such mechanisms at the nanoscale, we employed molecular dynamics simulations to study aggregation structure of surfactants (anionic sodium dodecyl sulfate (SDS)) at vacuum-water, water-graphite, water-silica, water-graphene and water-carbon nanotube interfaces. We also performed simulations of non-ionic mono dodecyl hexaethylene glycol (C12E6) at vacuum-water and water-silica interfaces for the purpose of comparing the results to those obtained for SDS at those interfaces. The results from the SDS aggregate morphologies at water-graphite (hydrophobic) and water-silica (hydrophilic) interfaces indicate that the aggregate morphology of SDS surfactants changes drastically with the change in the nature of the substrate. The comparison of results from water-graphite and water-graphene nanosheets and water-graphene nanoribbons indicate that lateral confinement effects are predominant at length scales comparable to the size of the SDS molecules, and diminish gradually as the substrate size increases. The effect of the substrate curvature on the SDS surface aggregate structure has been studied by simulating SDS at water-single walled carbon nanotube (SWNT) interfaces on SWNTs of different diameters and inside SWNTs. The results indicate that curvature, and also the surface coverage of the SDS surfactants influence the aggregate morphology. We also studied the aggregate structure of the flavin mononucleotide (FMN) molecules at water-SWNT interfaces. Finally, we predicted the effective interaction between two SWNTs in presence of SDS surfactants and FMN molecules at two different surface coverages. The knowledge of the effect of the different surfactant molecules on the effective interaction between nanotubes in aqueous dispersions will aid in the design of better surfactants to enhance the SWNTs dispersion and separation.
机译:表面活性剂是在一系列长度范围内用于许多应用中的重要的一类分子。采油,矿物采收,去污力是使用表面活性剂数十年的应用,而纳米颗粒的胶体分散体,纳米多孔材料的制备,碳纳米管的分散是表面活性剂的新应用,这些表面活性剂目前正日益受到关注。表面活性剂的聚集结构在确定纳米多孔材料的结构,表面活性剂分散胶体颗粒,碳纳米管和石墨烯纳米片的能力方面起着重要作用。为了更好地了解纳米级的这种机制,我们采用分子动力学模拟研究了表面活性剂(阴离子十二烷基硫酸钠(SDS))在真空-水,水-石墨,水-二氧化硅,水-石墨烯和水-碳纳米管上的聚集结构。接口。我们还对真空-水和水-二氧化硅界面上的非离子型单十二烷基六甘醇(C12E6)进行了模拟,目的是将结果与在这些界面上通过SDS获得的结果进行比较。 SDS在水-石墨(疏水)界面和水-二氧化硅(亲水)界面的聚集体形态结果表明,SDS表面活性剂的聚集体形态随基材性质的变化而急剧变化。水-石墨和水-石墨烯纳米片与水-石墨烯纳米带的结果比较表明,侧向限制作用在与SDS分子大小相当的长度尺度上是主要的,并且随着基底尺寸的增加而逐渐减小。通过在不同直径的SWNT上和内部的SWNT上的水单壁碳纳米管(SWNT)界面处模拟SDS,研究了基底曲率对SDS表面聚集体结构的影响。结果表明,曲率以及SDS表面活性剂的表面覆盖率均会影响聚集体形态。我们还研究了在水-SWNT界面处黄素单核苷酸(FMN)分子的聚集结构。最后,我们预测了在两种不同表面覆盖下,存在SDS表面活性剂和FMN分子时,两种单壁碳纳米管之间的有效相互作用。了解不同表面活性剂分子对水分散体中纳米管之间有效相互作用的影响的知识将有助于设计更好的表面活性剂,以增强SWNTs的分散和分离。

著录项

  • 作者

    Tummala, Naga Rajesh.;

  • 作者单位

    The University of Oklahoma.;

  • 授予单位 The University of Oklahoma.;
  • 学科 Engineering, Chemical.;Nanotechnology.;Physics, Condensed Matter.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 267 p.
  • 总页数 267
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 ;
  • 原文服务方 国家工程技术数字图书馆
  • 关键词

    ;

相似文献

  • 外文文献
站内服务

联系方式:18141920177 (微信同号)

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