Stable Solutions of Multiwalled Carbon Nanotubes Using an Azobenzene Dye

Abstract

We present a method to achieve stable dispersions of multiwalled carbon nanotubes (MWCNT) in tetrahydrofuran for several days. The physical chemistry of this method is based on the π-π stacking interactions between MWCNT and an azobenzene derivative, Disperse Orange 3 (DO3). Evidence of this interaction was obtained using UV-vis absorption spectroscopy. Our results suggest that there is a weight ratio DO3/MWCNT beyond which interactions are strong enough to achieve stable dispersions of MWCNT for at least 45 days.

A novel ferrocene-containing polymer based dispersant for noncovalent dispersion of multi-walled carbon nanotubes in chloroform

“…MWCNTs/PFcEMA/CHCl 3 dispersion was prepared by mixing 2.5 mL of 40 µg/mL PFcEMA/CHCl 3 solution with 2.5 mL of 20 µg/mL MWCNTs/CHCl 3 dispersion, followed by ultra-sonication at 20 o C for 60 min and then the resulting dispersion was diluted up to 10 mL. UV-vis spectrum of MWCNTs/PFcEMA dispersion was corrected by subtracting the absorbance of 5 µg/mL MWCNTs/CHCl 3 dispersion [26]. PFcEMA shows a characteristic energy absorption band at 242 nm, corresponding to the π-π * transition of the cyclopentadiene rings of the ferrocene.…”

Photobleaching effect in azo-dye containing epoxy resin films: the potentiality of carbon nanotubes as azo-dye dispensers

“…According to the previous results, the material with MWCNTs presents a different behavior with respect to the DO3 film reflecting that the presence of MWCNTs plays an important role in the optical response. In fact, the two observations previously mentioned in the description of Figure 3a could be explained in terms of the - interaction between DO3 molecules and MWCNTs [1,4]. This interaction generates that some fraction of DO3 molecules are preferentially in the vicinities of MWCNTs and less molecules are available for photoisomerization and thus for photobleaching.…”

“…Commercially available MWCNTs were purchased from Nanocyl (NC3100). Their length is about 1.5 μm and their diameter is around 20-40 nm [1]. MWCNTs were dried in a vacuum oven at 120° C during 3 h (in order to remove adsorbed water) and they were storage in vacuum at room temperature until used.…”

“…Particularly, the electronic structure of carbon nanotubes and azo-dye chromophores allows them to weakly interact via a non-covalent binding [1,2]. Among the many possible ways of working with carbon nanotubes and azo-dye chromophores, one alternative turns out from the addition of both carbon nanotubes and azo-dye molecules into a polymeric matrix [3,4].…”

Holographic gratings recorded in poly(lactic acid)/azo-dye films

“…The solvent used was Chloroform because both DO3 and PLA are soluble in it and, furthermore, it was already noticed that MWCNTs can be dispersed in a DO3/chloroform solution [23]. Reagent grade chloroform was purchased from Biopack (Argentina) and used as received.…”