Eur. Phys. J. E (2009) 29: 139-147
https://doi.org/10.1140/epje/i2009-10460-4

Regular Article

Fractal aggregates evolution of methyl red in liquid crystal

¹ Regional Laboratory LICRYL - INFM/CNR, Ponte Pietro Bucci, Cubo 33B, I-87036, Rende (CS), Italy
² Center of Excellence CEMIF.CAL, 87036, Rende (CS), Italy
³ Departamento de Física Aplicada, Universitat Politécnica de Catalunya, Campus Nord UPC, Modul B5, E-08034, Barcelona, Spain

^* e-mail: sorriso@fis.unical.it

Received: 26 January 2009
Revised: 30 March 2009
Accepted: 7 April 2009
Published online: 10 June 2009

Abstract

The spontaneous formation of dendritic aggregates is observed in a two-dimensional confined layered system consisting of a film composed of liquid crystal, dye and solvent cast above a polymer substrate. The observed aggregates are promoted by phase separation processes induced by dye diffusion and solvent evaporation. The growth properties of the aggregates are studied through the temporal evolution of their topological properties (surface, perimeter, fractal dimension). The fractal dimension of the completely formed structures, when they are coexistent with different types of structures, is consistent with theoretical and experimental values obtained for Diffusion-Limited Aggregates. Under different experimental conditions (temperature and local dye concentration) the structure forms without interactions with other kinds of structures, and its equilibrium fractal dimension is smaller. The fractal dimension is thus not a universal property of the observed structures, but rather depends on the experimental conditions.