Rsc_cc_c0cc02833a 1..3

Since Iijima’s report on carbon nanotubes (CNTs), they have been widely investigated due to their unique properties. In spite of many advantages, the practical applications of CNTs have been limited by their poor dispersibility in solvents, polymers, ceramics and metallic matrices. To overcome this limitation, many chemical and physical approaches to functionalized CNTs have been developed during last decades for improved compatibilities with both liquid and solid matrices. Among them, non-covalent approach was demonstrated to be more useful for electronic applications because electronic structures can be largely preserved for the noncovalently modified CNTs. Examples of non-covalent approaches include the wrapping of CNTs with conjugated polymers and the attachment of small aromatic molecules on CNTs via p–p stacking. It has also been well known that various amphiphilic materials, including surfactants, lipids, and polycations can be used to disperse singlewalled carbon nanotubes (SWNTs) in water. The capability of amphiphilic (macro)molecules to disperse SWNTs can be varied by tailoring the head and tail groups. For instance, Chen et al. reported the stabilization of SWNT dispersion via competitive adsorption or hybridization of small aromatic compounds with complementary DNA. We have previously reported the amphiphilic dendrons and dendrimers consisting of oligo(phenylene vinylene) (OPV) conjugated cores and oligo(ethylene oxide) (OEO) shells that showed unique solvatochromic and stimuli-responsive properties. In this study, we synthesized novel dendrimer with triphenylamine cores, benzothiadiazole branches and poly(ethylene oxide) (PEO) shells (Fig. 1a, also see Scheme S1 and synthesis details in ESIw). Then, we investigated its interactions with SWNTs and competitive adsorption phenomena on the graphitic surface of SWNTs with surfactants and lipids. Interestingly, when SWNTs and dendrimers were mixed together, the dispersibility of SWNTs was significantly increased in aqueous medium via simple sonication. Without dendrimer, SWNTs aggregate together in aqueous medium (Fig. 1b-left), whereas they are uniformly dispersed in the presence of dendrimer. The color of SWNTs and dendrimer solution was changed from orange dendrimer solution (Fig. 1b-middle) to deep-brown after uniform dispersion (Fig. 1b-right). The interactions between SWNTs and dendrimer are mainly due to the p–p stacking and van der Waals Fig. 1 (a) Chemical structures of amphiphilic dendrimer, the number average molecular weight, Mn, of poly(ethylene oxide) end is 550; (b) photograph of the pristine SWNTs (left), pure dendrimer (middle) and SWNT–dendrimer complex in water; (c) chemical structures of sodium dodecylbenzene sulfonate (SDBS), sodium dodecylsulfate (SDS) and lysophospholipid (LPC 18 : 0); (d) UV/Vis/NIR spectra of pure SWNTs, dendrimer and SWNT–dendrimer complex. Inset shows an enlarged view of the optical adsorption over 600–1200 nm for the pristine SWNTs and the SWNT–dendrimer complex; (e) PL spectra of pure dendrimer and SWNT–dendrimer complex in aqueous media after brief sonication. The concentrations of dendrimer and SWNTs in photograph were 125 mg ml 1 and 25 mg ml , respectively.