Adsorption of Nonuniformly Charged Fullerene-like Nanoparticles on Planar Polyelectrolyte Brushes in Aqueous Solutions

YY Hu and DP Cao, LANGMUIR, 25, 4965-4972 (2009).

DOI: 10.1021/la804302q

On the basis of the coarse grained model, we investigated the adsorption of nonuniformly charged fullerene-like nanoparticles on planar polyelectrolyte brushes (PEBs) in aqueous solution by using Brownian dynamics simulation. It is found that the electroneutral nanoparticles can be adsorbed by the PEB, which is attributed to the asymmetrical electrostatic interactions of the PEB with the positively charged sites and negatively charged sites of the fullerene-like nanoparticles. The simulation results indicated that the adsorption amount exhibits non- monotonic behavior with the dipole moment of nanoparticles. First, the adsorption amount increases with the dipole moment and then reaches the maximum at the dipole moment of mu = 10.45. Finally, the adsorption falls at the dipole moment of mu = 14.39. The reason may be that, at the extremely large dipole moment of mu = 14.39, the fullerene-like nanoparticles aggregate together to form a big cluster in the bulk phase, which can be confirmed by the extremely high peak in the radial distribution function between nanoparticles. Accordingly, it is difficult for nanoparticles to enter into the PEB at the dipole moment of mu = 14.39. In addition, it is also found that the brush grafting density is an important factor affecting the brush thickness.

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