Investigating the effectiveness of PEO/PPO based copolymers as dispersing agents for graphitic carbon black aqueous dispersions

Improved Coarse-Grained Model for Nanoparticles Based on the Martini Force Field and Its Application in Molecular Dynamics Simulation on Gel Ink

Research on the dispersion and stability of nanoparticles in liquid media is one of the key subjects for nanomaterial utilization. In consideration of the preponderance of coarse-grained (CG) molecular dynamics (MD) simulation in following and understanding the structure and dynamics on the nanoscale, an improved CG model for nanoparticles based on the Martini force field is established to facilitate the more extensive applications of this simulation method and further studies on complex nanoparticle liquid systems. Gel ink is selected as the liquid system for nanoparticles to validate the improved CG model on the one hand and introduce the CGMD simulation method into the studies of this system on the other. The calculation shows that the improved model can provide relatively precise results and has good computational stability. The effect mechanisms of the thickener and disperser on the carbon black nanoparticle are similar, namely the result of a delicate balance between the interaction of the thickener/disperser with the carbon black nanoparticle and the interaction of the thickener and disperser with each other. Furthermore, the phase assimilating effect of disperser molecules is key for separating the agglomerated carbon black nanoparticles; thereafter, the space steric hindrance effect and the electrostatic hindrance effect play main roles in maintaining the dispersion of carbon black nanoparticles.

Adsorption of F127 onto single-walled carbon nanotubes characterized using small-angle neutron scattering

Aqueous single-walled carbon nanotube dispersions are often made using polymers from the pluronic family of amphiphilic block copolymers; however, relatively few studies have been conducted using small-angle neutron scattering techniques to discover the mechanism by which they act. SANS results reported here show that a relatively simple core-shell cylinder model can be used to fit data successfully at different contrasts. The results across all contrasts showed that the best fit gave an inner nanotube radius of 10 Å, corresponding to small nanotube bundles with a small amount of water present (20%), and a polydisperse adsorbed layer thickness of 61 Å, with a water content of 94% in the adsorbed layer. The data fitting is thus consistent with a small SWCNT bundle surrounded by an extended and water-swollen F127 adsorbed layer. Comparing the scattering from F127/SWCNT at different contrasts, it has been found that the polymer-decorated SWCNTs are contrast matched at a D2O/H2O volume ratio of 0.36:0.64, corresponding to a scattering-length density of 1.92 × 10(-6) Å(-2).

Improvement of crystallization and particle size distribution of boric acid in the processing of a boron carbide precursor

Nano boric acid crystal fabrication from the combined effect of hexane and dispersant.

Numerical and experimental study of suspensions containing carbon blacks used as conductive additives in composite electrodes for lithium batteries

Suspensions of carbon blacks and spherical carbon particles are studied experimentally and numerically to understand the role of the particle shape on the tendency to percolation. Two commercial carbon blacks and one lab-synthesized spherical carbon are used. The percolation thresholds in suspensions are experimentally determined by two complementary methods: impedance spectroscopy and rheology. Brownian dynamics simulations are performed to explain the experimental results taking into account the fractal shape of the aggregates in the carbon blacks. The results of Brownian dynamics simulations are in good agreement with the experimental results and allow one to explain the experimental behavior of suspensions.