Zhang W, Shiozawa H, Wu C W, Hamerton I, Cox D C, Silva S R P
Nanoelectronics Centre, Advanced Technology Institute, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom.
J Nanosci Nanotechnol. 2012 Jan;12(1):84-90. doi: 10.1166/jnn.2012.5130.
Single walled carbon nanotubes (SWCNTs) were dispersed in water and attached to nylon fabrics by a dip-drying procedure; scanning electron microscopy and Raman spectroscopy suggest the attachment of the SWCNTs. The electrical resistance of the functionalized fabrics is found to be pH-dependent, which is correlated with the quantity of SWCNTs dispersed in water at different values of pH. This can be further ascribed to the influence of the pK(a) of the acid (e.g., acetic acid in this study) used to tune pH. The acid may affect the dispersion of SWCNTs through two different mechanisms: (1) the free protons may protonate the amine and/or sulfonate group in the dye molecules, resulting in a variety of interactions among the dye molecules, SWCNTs and water molecules and (2) the resulting ions may increase the ionic strength of the solution, compressing the electric double layers of SWCNT colloids and thus impairing their stability. The former possibility is ruled out by data obtained using X-ray photoelectron spectroscopy, Raman spectroscopy, and ultraviolet-visible-near infrared spectroscopy; thus the latter is proposed to account for the experimental results. The colour strength of the functionalized fabrics increases with increasing pH, which is in agreement with their measured electrical properties.
单壁碳纳米管（SWCNTs）分散于水中，并通过浸干工艺附着在尼龙织物上；扫描电子显微镜和拉曼光谱表明SWCNTs已附着。发现功能化织物的电阻与pH有关，这与不同pH值下分散在水中的SWCNTs数量相关。这可进一步归因于用于调节pH的酸（如本研究中的乙酸）的pK(a)的影响。酸可能通过两种不同机制影响SWCNTs的分散：（1）游离质子可能使染料分子中的胺基和/或磺酸根基团质子化，导致染料分子、SWCNTs和水分子之间产生多种相互作用；（2）产生的离子可能增加溶液的离子强度，压缩SWCNT胶体的双电层，从而损害其稳定性。使用X射线光电子能谱、拉曼光谱和紫外-可见-近红外光谱获得的数据排除了前一种可能性；因此提出后一种可能性来解释实验结果。功能化织物的色强度随pH升高而增加，这与它们测得的电学性质一致。
