关于在水性表面活性剂溶液中的单壁碳纳米管可控功能化的二氧化吸附的分子视角
Shangchao Lin1, Andrew J Hilmer, Jonathan D Mendenhall
1Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Journal of the American Chemical Society
|April 26, 2012
概括
控制单壁碳纳米管 (SWCNTs) 的二氧化盐功能化是应用的关键. 这项研究模拟了SWCNT与表面活性剂上的二氧化离子吸附,揭示了预测功能化程度的结合亲和力.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术 纳米技术
- 物理化学 物理化学
背景情况:
- 单壁碳纳米管 (SWCNTs) 的功能化改变了各种应用的特性.
- 由于复杂的表面相互作用,控制SWCNT上的二氧化盐功能化具有挑战性.
研究的目的:
- 了解和模拟涂有各种表面活性剂的SWCNT表面上的二氧化离子吸附.
- 建立一个预测和控制SWCNT功能化程度的框架.
主要方法:
- 分子动力学 (MD) 模拟以确定二氧化吸附自由能量.
- 模拟预测的实验验证.
- 功能化程度的平衡反应建模.
主要成果:
- 表面活性剂的选择显著影响着二氧化吸附和SWCNT功能.
- 通过模拟预测的绑定亲和力与观察到的功能化水平相关.
- 与表面活性剂头组的协同结合影响了离子亲和力.
结论:
- 综合模拟-建模方法可以准确预测SWCNT的功能程度.
- 该框架为优化针对性SWCNT功能化的实验条件提供了指导.
- 了解表面活性剂-SWCNT-diazonium相互作用对于量身定制的纳米材料设计至关重要.
相关概念视频
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
Diazonium Group Substitution: –OH and –H
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
Treating arylamines with nitrous acid gives aryldiazonium salts that are effective substrates in nucleophilic aromatic substitution reactions. The diazonio group in these salts can be easily displaced by different nucleophiles, yielding a wide variety of substituted benzenes. The leaving group departs as nitrogen gas, and this easy elimination is the driving force for the substitution reaction.
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Arenediazonium substitution reactions occur when the diazonium group is substituted by various functional groups such as halides, hydroxyl, nitrile, etc. For instance, arenediazonium salts react with copper(I) salts of chloride, bromide, or cyanide to form corresponding aryl chlorides, bromides, and nitriles. These reactions are named Sandmeyer reactions. Although the mechanism of this reaction is complicated, as illustrated in Figure 1, they are believed to progress via an aryl copper...


