Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: Crystallization, Nucleation and Self Assembly I

CPP 14.11: Vortrag

Dienstag, 12. März 2013, 12:15–12:30, H39

Spin Casting of Dilute Solutions to Control Nucleation and Growth — •Stefan Karpitschka, Constans Weber, and Hans Riegler — MPI für Kolloid- und Grenzflächenforschung, Potsdam, Germany

We analyze the spin casting of dilute (ideal) binary mixtures of non-volatile solutes in volatile solvents as a prototype for evaporation-controlled processes that are increasingly used to deposit specifically structured (sub)monolayers (evaporation-induced self-assembly). The first analytical description of the thinning of a volatile liquid film simultaneously subject to spinning and evaporation is presented. It shows, that the duration of a spin casting process is linked to the process parameters via power laws. A diffusion-advection model leads analytically to the equation governing the spatio-temporal evolution of the internal film composition. Its solution reveals that the solute concentration enrichment, its gradient, and its time evolution are related to the process parameters via power laws. The physics behind the power laws is uncovered and discussed [1]. This reveales universal insights into the interplay between the control parameters and their impact on the spatio-temporal evolution of the film composition of diluted mixtures. It also offers palpable guidelines to better understand and control the spin casting of non-ideal solutions. Experiments are presented which support the theoretical findings.

[1] S. Karpitschka, C. Weber, H. Riegler, PRL (2012), in revision.