A detailed study of the interaction mechanism between carbon nanotubes and physically adsorbed block copolymers is presented. The combination of experimental observations, computer simulations and theory suggests that while the solvophobic blocks adsorb to the nanotubes by a nonwrapping mechanism, the dangling (solvophilic) blocks provide a steric barrier that leads to the formation of stable dispersions of individual single walled carbon nanotubes (SWNT) and multiwalled carbon nanotubes (MWNT) above a threshold concentration of the polymer. The observed threshold concentration depends on the length of the solvophobic blocks, and it is higher for MWNT as compared to SWNT. Theory suggests that the latter is a consequence of dimensional considerations. Spectroscopic characterization of the dispersions indicate that the dispersing block polymers do not alter the electronic structure of the well dispersed individual SWNT, supporting the model of nonspecific adsorption of the polymer to the tube driven by van der walls type interactions. The study presented here offers a generic scheme for optimization of the structure and composition of block copolymers used for dispersion of CNT in different media.

The self-assembly (SA) of amphiphilic block copolymers (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)) was investigated in dispersions of single-walled and multiwalled carbon nanotubes (SWNT and MWNT, respectively) as a function of temperature. Differential scanning calorimetry (DSC) was used for characterization of the thermal behavior of the combined polymers-nanostructures system, and spin-probe electron paramagnetic resonance (EPR) was employed for probing the local dynamic and polarity of the polymer chains in the presence of nanostructures. It was found that SWNT and MWNT modify the temperature, enthalpy, and dynamic behavior of polymer SA. In particular, SWNT were found to increase the cooperativity of aggregating chains and dominate aggregate dynamics. MWNT reduced the cooperativity, while colloidal carbon black additives, studied for comparison, did not show similar effects. The experimental observations are consistent with the suggestion that dimensional matching between the characteristic radius of the solvated polymer chains and the dimensions of additives dominate polymer SA in the hybrid system.

Impregnated cotton textiles with a MOF based nanocomposite revealed a supreme multi-functionality to adsorb/degrade/sense vapors of a nerve agent surrogate.