Key role of the linker in pyrene-linker-carboxylate surfactants for the efficient aqueous dispersion of multiwalled carbon nanotubes
Key role of the linker in pyrene-linker-carboxylate surfactants for the efficient aqueous dispersion of multiwalled carbon nanotubes
复制标题
芘-连接基-羧酸盐表面活性剂中连接基对多壁碳纳米管有效水分散体的关键作用
作者：
Welsh D
本研究证实了新型表面活性剂1-13中疏水单元和亲水单元之间的连接基团的结构在多壁碳纳米管（MWNTs）在水中的吸附中起着重要作用。碳纳米管的两亲性表面活性剂中连接基团的系统变化以前没有研究过。在本系列中，疏水单元衍生自芘，亲水单元包含1-9个羧酸酯基团，并且连接基基于酰胺或醚部分。所得的MWNT-表面活性剂分散体，高达约100 μ g/ml的浓度和效率。分别为160 mg L-1和近50%，已通过紫外可见吸收光谱研究进行了表征，提供了详细的结构-性能关系，而透射电子显微镜（TEM）用于确认MWNT分散良好。对于许多新的表面活性剂，与商业表面活性剂相比，观察到增强的分散效率。分散体的效率受连接体的存在、官能度和特别是长度以及末端羧酸酯单元的数量的影响。钠、钾和钙阳离子对分散行为的显着影响可以通过金属离子与表面活性剂之间的相互作用和离子屏蔽机制来解释。我们还表明，MWNT-表面活性剂分散液的pH值可以通过分别加入酸和碱可逆地“关闭”和“打开”。溶剂化能ΔES的理论计算支持了实验结果。该研究代表了在设计用于碳基材料的高效水分散体的多功能表面活性剂方面的重大进展。
This study establishes that the structure of the linker group between the hydrophobic and hydrophilic units in the new surfactants 1–13 plays an important role in the dispersibility of multiwalled carbon nanotubes (MWNTs) in water. The systematic variation of the linker group in amphiphilic surfactants for carbon nanotubes has not been previously investigated. In the present series, the hydrophobic unit is derived from pyrene, the hydrophilic unit comprises 1–9 carboxylate groups and the linker is based on amide or ether moieties. The resulting MWNT–surfactant dispersions, up to concentrations and efficiencies of ca. 160 mg L−1 and almost 50%, respectively, have been characterised by UV-vis absorption spectroscopy studies which provide detailed structure–property relationships, while transmission electron microscopy (TEM) was used to confirm that the MWNTs were well dispersed. For many of the new surfactants enhanced dispersion efficiency is observed compared to commercial surfactants. The efficiency of the dispersion is affected by the presence, functionality and particularly the length of the linker, and also the number of terminal carboxylate units. The marked effect of sodium, potassium and calcium cations on the dispersion behaviour is explained by interactions between the metal ions and the surfactant and an ionic screening mechanism. We also demonstrate that the dispersibility of the MWNT–surfactant dispersions can be reversibly switched ‘off’ and ‘on’ by addition of acid and base, respectively. The experimental results are supported by theoretical calculations of solvation energy ΔES. This study represents a significant advance in the design of multi-functional surfactants for efficient aqueous dispersions of carbon-based materials.
登录
查看更多内容
影响因子：
4.4
作者：
Bailey, Steven;Visontai, David;Chappell, David
通讯作者：
Chappell, David
电弧放电单壁碳纳米管的分散和表征——走向导电透明薄膜。
影响因子：
6.7
作者：
Benedikt Rösner;D. M. Guldi;Jun Chen;A. Minett;Rainer H. Fink
通讯作者：
Rainer H. Fink
影响因子：
6.7
作者：
J T. Yoo;H. Ozawa;T. Fujigaya and N. Nakashima
通讯作者：
T. Fujigaya and N. Nakashima
25 °C 水中氯化钠和氯化钾与某些酰胺相互作用的焓
DOI：
--
发表时间：
1989
期刊：
影响因子：
--
作者：
K. Davis;M. A. Gallardo;T. H. Lilley
通讯作者：
T. H. Lilley
25°C 水中某些酰胺与甲酸铵的相互作用焓 离子基团与肽和疏水基团之间的相互作用
DOI：
--
发表时间：
1997
期刊：
影响因子：
--
作者：
Javier Fernández;.. N. García;T. H. Lilley;H. Linsdell
通讯作者：
H. Linsdell