Transient coarsening and the motility of optically heated Janus colloids in a binary liquid mixture

Gomez-Solano, Juan Ruben; Roy, Sutapa; Araki, Toshimitsu; Dietrich, S.; Maciołek, Anna

doi:10.1039/d0sm00964d

Cited by 16 publications

(14 citation statements)

References 48 publications

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“…The power-law exponent ≈ 2, as predicted from both purely diffusive and hydrodynamic models, is in excellent agreement with the experiment. This agreement supports the existence of a generic mechanism of the initial process connected to the formation of surface layers [38]. On the other hand, the relaxation to equilibrium after switching off the illumination (OFF process) is stretched exponential with a characteristic time decreasing as the illumination power increases, which we attribute to the temperature gradient previously formed by the laser-induced heating of the particle's golden cap.…”

Section: Introductionsupporting

confidence: 83%

Relaxation to steady states of a binary liquid mixture around an optically heated colloid

Araki,

Gomez-Solano,

Maciołek

2022

Preprint

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We study the relaxation dynamics of a binary liquid mixture near a light-absorbing Janus particle after switching on and off illumination using experiments and theoretical models. The dynamics is controlled by the temperature gradient formed around the heated particle. Our results show that the relaxation is asymmetric: the approach to a nonequilibrium steady state is much slower than the return to thermal equilibrium. Approaching a nonequilibrium steady state after a sudden temperature change is a two-step process that overshoots the response of spatial variance of the concentration field. The initial growth of concentration fluctuations after switching on illumination follows a power law in agreement with the hydrodynamic and purely diffusive model. The energy out-flow from the system after switching off illumination is well described by a stretched exponential function of time with characteristic time proportional to the ratio of the energy stored in the steady state to the total energy flux in this state.

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Section: Introductionsupporting

confidence: 83%

Relaxation to steady states of a binary liquid mixture around an optically heated colloid

Araki,

Gomez-Solano,

Maciołek

2022

Preprint

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“…In this paper, we present a strategy that takes advantage of Marangoni effects at small scales. A temperature-induced interfacial tension gradient is known to cause an interfacial stress generating thin film flow [26][27][28][29] and droplets or colloids motion [30][31][32][33][34][35], thereby affecting the phase separation kinetics [36]. Note that concerning the phase transition of a pure fluid, the mechanisms of droplets or bubbles migration in a temperature gradient are not induced by Marangoni stresses [37,38].…”

Section: Introductionmentioning

confidence: 99%

Phase separation of an ionic liquid mixture assisted by a temperature gradient

Pascual

Poquet²,

Vilquin³

et al. 2021

Phys. Rev. Fluids

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“…We would like to point out that, since the parameters characterizing the operation of the heat engine presented in this paper are representative of typical soft matter systems, we expect that this process can be realized in a straightforward manner by use of optical tweezers [52]. Similar ideas could be extended to Brownian particles in non-linear potentials [82], and active Brownian heat engines [32] functioning in complex fluids, which could be implemented by means of light-activated colloids in non-Newtonian liquids [69,[83][84][85][86] and hot Brownian particles [87][88][89].…”

Section: Summary and Final Remarksmentioning

confidence: 92%

Work Extraction and Performance of Colloidal Heat Engines in Viscoelastic Baths

Gomez-Solano

2021

Front. Phys.

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A colloidal particle embedded in a fluid can be used as a microscopic heat engine by means of a sequence of cyclic transformations imposed by an optical trap. We investigate a model for the operation of such kind of Brownian engines when the surrounding medium is viscoelastic, which endows the particle dynamics with memory friction. We analyze the effect of the relaxation time of the fluid on the performance of the colloidal engine under finite-time Stirling cycles. We find that, due to the frequency-dependence of the friction in viscoelastic fluids, the mean power delivered by the engine and its efficiency can be highly enhanced as compared to those in a viscous environment with the same zero-shear viscosity. In addition, with increasing fluid relaxation time the interval of cycle times at which positive power output can be delivered by the engine broadens. Our results reveal the importance of the transient behavior of the friction experienced by a Brownian heat engine in a complex fluid, which cannot be neglected when driven by thermodynamic cycles of finite duration.

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Transient coarsening and the motility of optically heated Janus colloids in a binary liquid mixture

Abstract: A gold-capped Janus particle suspended in a near-critical binary liquid mixture can self-propel under illumination. We have immobilized such a particle in a narrow channel and carried out a combined...

Cited by 16 publications

References 48 publications

Relaxation to steady states of a binary liquid mixture around an optically heated colloid

Relaxation to steady states of a binary liquid mixture around an optically heated colloid

Phase separation of an ionic liquid mixture assisted by a temperature gradient

Work Extraction and Performance of Colloidal Heat Engines in Viscoelastic Baths

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