Wrapping of Single‐Walled Carbon Nanotubes with A‐B‐A Block Telomers

Abstract

Summary: Single‐walled carbon nanotubes (SWNTs) mechanically dispersed in HEPES buffer were incubated with a dispersion of A‐B‐A block telomers, composed of 2‐methacryloyloxyethyl‐D‐glucopyranoside telomers (A block) and a styrene telomer (B block), which had been prepared by the macroinitiator technique. After the incubation, the polymer‐wrapped SWNT could be stably dispersed in the buffer without any precipitation for several months. The glucose residue above the SWNT was definitely recognized by lectin (Concanavalin A) as proven by the increase in turbidity. Using a similar procedure, a block telomer composed of N‐isopropylacrylamide telomers (A block) and a styrene telomer (B block) could easily be deposited onto the SWNT. A temperature‐responsive aggregation and the subsequent precipitation of the modified SWNT could clearly be observed. The usage of the block‐telomer examined here would be promising for the preparation of stable dispersions of SWNTs with various functions. magnified image

pH responsive MWCNT–star terpolymer nanohybrids

“…Solubilization of CNTs by micelle encapsulation has been accomplished using a PS-b-PAA copolymer. 28 The ability of block copolymers to wrap CNTs has been exhibited by triblock copolymers like PNIPAM-b-PS-b-PNIPAM, 70 poly(ethylene-cobutylene)-b-poly(methyl methacrylate-co-pyrene methyl 2-methyl-2-propenoate) diblocks 71 and amphiphilic pluronic PEO-b-PPO-b-PEO 33,34 (where PPO: poly(propylene oxide)) and poly(ethylene glycol)-b-poly(propylene sulde) 35 copolymers. Physical adsorption of a PS-b-PMAA copolymer on CNTs was realized by a non-wrapping mechanism.…”

Thermodynamically stable, size selective solubilization of carbon nanotubes in aqueous solutions of amphiphilic block copolymers

“…Extensive research in the last 5 years has focused on two general approaches to dispersing CNTs. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] One is surface treatment of the nanotubes coupled with covalent functionalization. The main disadvantages of this approach are the disruption of the extended conjugation in nanotubes and the reduction in nanotube lengths, both of which severely undermine the electrical and mechanical properties of the nanotubes.…”

Block‐Copolymer‐Assisted Solubilization of Carbon Nanotubes and Exfoliation Monitoring Through Viscosity

“…The exfoliation is often achieved prior to mixing with the polymer, e.g., through covalent9 or non‐covalent10 chemical modification of the SWNT surface. A convenient way of obtaining a stable SWNT dispersion is through sonification combined with interactions of nanotubes with macromolecules like poly(vinyl pyrrolidone) and poly(styrene sulfonate),11 poly(metaphenylenevinylene) and derivatives,12–15 poly[(vinylidene fluoride)‐ co ‐trifluroethylene],16 amylose,17 arabic gum,18 gelatin,19 block copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO),20,21 and ABA‐type block telomers 22. Such solubilization is proposed to occur through wrapping of the polymers around the SWNTs12,14,15,19,23 or via steric stabilizations 17,21.…”