Abstract.: A thermal diffusion process occurring in a binary liquid mixture is accompanied by long ranged non-equilibrium concentration fluctuations. The amplitude of these fluctuations at large length scales can be orders of magnitude larger than that of equilibrium ones. So far non-equilibrium fluctuations have been mainly investigated under stationary or quasi-stationary conditions, a situation that allows to achieve a detailed statistical characterization of their static and dynamic properties. In this work we investigate the kinetics of growth of non-equilibrium concentration fluctuations during a transient thermodiffusion process, starting from a configuration where the concentration of the sample is uniform. The use of a large molecular weight polymer solution allows to attain a slow dynamics of growth of the macroscopic concentration profile. We focus on the development of fluctuations at small wave vectors, where their amplitude is strongly limited by the presence of gravity. We show that the growth rate of non-equilibrium fluctuations follows a power law Rf(q,t)∝1t as a function of time, without any typical time scale and independently of the wave vector. We formulate a phenomenological model that allows to relate the rate of growth of non-equilibrium fluctuations to the growth of the macroscopic concentration profile in the absence of arbitrary parameters.
Kinetics of growth of non-equilibrium fluctuations during thermodiffusion in a polymer solution / M. Carpineti, M. Sabato, F. Croccolo, A. Vailati. - In: THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER. - ISSN 1292-8941. - 42:2(2019 Feb).
|Titolo:||Kinetics of growth of non-equilibrium fluctuations during thermodiffusion in a polymer solution|
CARPINETI, MARINA (Primo) [Writing – Original Draft Preparation] (Corresponding)
VAILATI, ALBERTO (Ultimo) [Supervision]
|Parole Chiave:||Topical issue: Thermal Non-Equilibrium Phenomena in Soft Matter; Biotechnology; Biophysics; Chemistry (all); Materials Science (all); Surfaces and Interfaces|
|Settore Scientifico Disciplinare:||Settore FIS/03 - Fisica della Materia|
|Data di pubblicazione:||feb-2019|
|Data ahead of print / Data di stampa:||27-feb-2019|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1140/epje/i2019-11786-x|
|Appare nelle tipologie:||01 - Articolo su periodico|
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