μμμFig. 4. Average agglomerate diameter (D mean) and UV–vis peak intensity of aque-ous 0.5 wt% CNT suspensions after (a) 30 (b) 60 and (c) 90 min of sonication, as afunction of SDBS/CNT ratio.of sonication. A significant increase in peak intensity is obtainedwith the increase of SDBS/CNT ratio from 0.5 to 1 while furtherincrease in surfactant concentration again does not improve thepeak intensity greatly. An interesting increase in Dmean is observedat a ratio of 1, the property reduces significantly at a correspondingratio of 2. By observation of PDI data, it is found that all suspen-sions are poly-disperse after 60 min of sonication. After 90 min ofsonication, a parallel shift in peak intensity towards higher val-ues is obtained, while Dmean remains unchanged with respectto the relative surfactant concentration (Fig. 4c). Based on poly-dispersity data, it can be concluded that low SDBS concentrations