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).

Kinetics of growth of non-equilibrium fluctuations during thermodiffusion in a polymer solution

Carpineti, Marina;Vailati, Alberto
2019-02

Abstract

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.
Topical issue: Thermal Non-Equilibrium Phenomena in Soft Matter; Biotechnology; Biophysics; Chemistry (all); Materials Science (all); Surfaces and Interfaces
Settore FIS/03 - Fisica della Materia
27-feb-2019
THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER
Article (author)
File in questo prodotto:
File Dimensione Formato  
Carpineti Topical_Contribution.pdf

embargo fino al 28/05/2020

468.38 kB Adobe PDF Visualizza/Apri
Carpineti2019_Article_KineticsOfGrowthOfNon-equilibr.pdf

non disponibili

558.48 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/634443
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 3
  • ???jsp.display-item.citation.isi??? 2
social impact