The role of surface properties and internal degrees of freedom on the thermophoresis of Janus particles*

From the early observations of thermodiffusion by Ludwig and Soret [1,2] to the study of thermal polarization [3,4], temperature fields have been identified as key molecular driving forces. In this context, Janus particles have received much attention due to their tunable heterogeneity, which determines their thermal response and motion rectification. While theoretical work on Janus particles has focused on surface properties [5], we have shown that the internal mass distribution plays an important role in the thermal orientation effect [6]. In this work, we demonstrate how both interfacial properties as well as internal degrees of freedom must be considered in order to understand the emerging behaviour of Janus colloids under temperature gradients, opening new avenues for their rational design. 

[1] C. Ludwig, Sitz. ber. Akad. Wiss. Wien Math.-Nat. wiss. Kl., 20 (1856), 539. 

[2] C. Soret. Arch. Sci. Phys. Nat. (Geneve), 2 (1879), 48. 

[3] F. Bresme, A. Lervik, D. Bedeaux and S. Kjelstrup, Phys. Rev. Lett., 101 (2008), 020602. 

[4] F. Römer, F. Bresme, J. Muscatello, D. Bedeaux and J.M. Rubí, Phys. Rev. Lett., 108 (2012), 105901. 

[5] T. Bickel, G. Zecua and A. Würger, Phys. Rev. E., 89 (2014), 050303. 

[6] J.D. Olarte-Plata and F. Bresme, J. Chem. Phys., 152 (2020), 204902.