TY - JOUR
T1 - Molecular dynamics simulation of the forces between colloidal nanoparticles in n -decane solvent
AU - Qin, Yong
AU - Fichthorn, Kristen A.
N1 - Funding Information:
This work was funded by an EPA Star Grant Program (Grant No. R-8290501) and the NSF (Grant No. CCR0303976).
PY - 2007
Y1 - 2007
N2 - Molecular dynamics is utilized to simulate solvation forces between two nanoparticles immersed in liquid n -decane. Three types of solvophilic nanoparticles are investigated with sizes in the 1-6 nm range: small and large amorphous spheres and crystalline cubes. We find that the solvation forces are negligible for the small spheres, which have diameters comparable to the end-to-end distance of all-trans decane, and we attribute this to the inability of the small spheres to induce decane ordering in the interparticle gap. The cubic nanoparticles (and to a lesser extent, the large spheres) are able to induce the formation of solidlike, n -decane layers in their gap for certain nanoparticle separations, and the transition between layered and disordered structures leads to solvation forces that oscillate between repulsion and attraction as the nanoparticle separation is varied. We find that the Derjaguin approximation [B. V. Derjaguin, Kolloid-Z. 69, 155 (1934)] is not effective at describing the dependence of the solvation forces on nanoparticle size and shape-contrasting results from a previous study involving these nanoparticles in Lennard-Jones solvent [Y. Qin and K. A. Fichthorn, J. Chem. Phys. 119, 9745 (2003)]. In particular, we find that for decane, the magnitude of the repulsive solvation forces is sensitive to nanoparticle size and shape, a phenomenon we attribute to the size and rigid-rod structure of n -decane, which makes its ordering in the interparticle gap sensitive to the size and the surface roughness of the nanoparticles.
AB - Molecular dynamics is utilized to simulate solvation forces between two nanoparticles immersed in liquid n -decane. Three types of solvophilic nanoparticles are investigated with sizes in the 1-6 nm range: small and large amorphous spheres and crystalline cubes. We find that the solvation forces are negligible for the small spheres, which have diameters comparable to the end-to-end distance of all-trans decane, and we attribute this to the inability of the small spheres to induce decane ordering in the interparticle gap. The cubic nanoparticles (and to a lesser extent, the large spheres) are able to induce the formation of solidlike, n -decane layers in their gap for certain nanoparticle separations, and the transition between layered and disordered structures leads to solvation forces that oscillate between repulsion and attraction as the nanoparticle separation is varied. We find that the Derjaguin approximation [B. V. Derjaguin, Kolloid-Z. 69, 155 (1934)] is not effective at describing the dependence of the solvation forces on nanoparticle size and shape-contrasting results from a previous study involving these nanoparticles in Lennard-Jones solvent [Y. Qin and K. A. Fichthorn, J. Chem. Phys. 119, 9745 (2003)]. In particular, we find that for decane, the magnitude of the repulsive solvation forces is sensitive to nanoparticle size and shape, a phenomenon we attribute to the size and rigid-rod structure of n -decane, which makes its ordering in the interparticle gap sensitive to the size and the surface roughness of the nanoparticles.
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U2 - 10.1063/1.2776259
DO - 10.1063/1.2776259
M3 - Article
C2 - 17935443
AN - SCOPUS:35248831756
SN - 0021-9606
VL - 127
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 14
M1 - 144911
ER -