Microscopic dynamics of the orientation of a hydrated nanoparticle in an electric field

• Published in: Physical review letters Vol. 103; no. 20; p. 207801
• Main Authors: Daub, Christopher D, Bratko, Dusan, Ali, Towshif, Luzar, Alenka
• Format: Journal Article
• Language: English
• Published: United States 13.11.2009
• Subjects: Computer Simulation; Electricity; Microscopy - methods; Models, Chemical; Nanoparticles - chemistry; Water - chemistry
• DOI: 10.1103/PhysRevLett.103.207801

We use atomistic simulations to study the orientational dynamics of a nonpolar nanoparticle suspended in water and subject to an electric field. Because of the molecular-level effects we describe, the torque exerted on the nanoparticle exceeds continuum-electrostatics-based estimates by about a factor of 2. The reorientation time of a 16.2 x 16.2 x 3.35 A(3) nanoparticle in a field |E| > 0.015 V/A is an order of magnitude less than the field-free orientational time (approximately 1 ns). Surprisingly, the alignment speed is nearly independent of the nanoparticle size in this regime. These findings are relevant for design of novel nanostructures and sensors and development of nanoengineering methods.