Charged particle separation by an electrically tunable nanoporous membrane

• Published in: Nanotechnology Vol. 25; no. 14; pp. 145201 - 9
• Main Authors: Jou, Ining A, Melnikov, Dmitriy V, Nadtochiy, Anna, Gracheva, Maria E
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 11.04.2014; Institute of Physics
• Subjects: Brownian dynamics; Charge; Charged particles; Computer Simulation; Condensed matter: structure, mechanical and thermal properties; dielectrophoresis; Dynamical systems; Dynamics; electro-osmotic; Electrophoresis; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Membranes; Membranes, Artificial; Models, Molecular; nanoparticle; Nanoparticles - analysis; nanopore; Nanopores - ultrastructure; Nanostructure; Permeability; Physics; Porosity; semiconductor; Semiconductors; Separation; Static Electricity; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Electric potential; Semiconductor materials; Potential distribution; Particle motion; Fluid flow; Selectivity; Nanostructures; Permeability; Particle separation; Brownian motion; Electrolytes; Dielectrophoresis; Charged particles; Electrostatic potential; Nanoporosity
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/25/14/145201

We study the applicability of an electrically tunable nanoporous semiconductor membrane for the separation of nanoparticles by charge. We show that this type of membrane can overcome one of the major shortcomings of nanoporous membrane applications for particle separation: the compromise between membrane selectivity and permeability. The computational model that we have developed describes the electrostatic potential distribution within the system and tracks the movement of the filtered particle using Brownian dynamics while taking into consideration effects from dielectrophoresis, fluid flow, and electric potentials. We found that for our specific pore geometry, the dielectrophoresis plays a negligible role in the particle dynamics. By comparing the results for charged and uncharged particles, we show that for the optimal combination of applied electrolyte and membrane biases the same membrane can effectively separate same-sized particles based on charge with a difference of up to 3 times in membrane permeability.