Abstract
A thermodynamic equilibrium sensor is proposed that measures the ratio of the number of elementary charges z to the mass m of charged solutes such as charged colloids and nanoparticles. The sensor comprises a small, membrane-encapsulated salt solution volume that absorbs neutral salt molecules in response to the release of mobile counter-ions by charge carriers in the surrounding suspension. The sensor state emerges as a limiting case of the equilibrium salt imbalance, and the ensuing osmotic pressure difference, between arbitrary salt and suspension volumes. A weight concentration of charge carriers c is predicted to significantly increase the sensor's salt number density from its initial value ρs,0 to ρRs, according to the relation (ρRs/ρs,0)2 - 1 = zc/mρs,0, under the assumption that the mobile ions involved in the thermodynamic sensor-suspension equilibrium are ideal and homogeneously distributed.
Original language | English |
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Pages (from-to) | 103-121 |
Number of pages | 19 |
Journal | Faraday discussions |
Volume | 181 |
DOIs | |
Publication status | Published - 1 Aug 2015 |