The direct interaction between two droplets or two bubbles represents an important elementary process in foams or emulsions. The knowledge about the stability of the film between them is essential to prevent coalescence. There are not many tools known in literature which allow to study this [1]. We present a drop and bubble micro manipulator (DBMM) as a new experimental tool for the quantitative analysis of the interaction between two drops or two bubbles, or even between a single drop and a single bubble, in a liquid medium. For each drop or bubble, a coarse and a very fine dosing system exists in order to control their size or change it in respect to a given protocol. Accurate pressure sensors for each drop/bubble allow to record changes in the capillary pressure and also to detect coalescence [2]. The DBMM also allows to study the stability of liquid films between drops or bubbles under the effect of external perturbations, i.e. a harmonic oscillation with a given frequency and amplitude can be generated in the drops/bubbles in order to find critical conditions for the coalescence. The instrument can be equipped with a fast video camera in order to monitor fast processes such as the coalescence. Situation at the tip of two oppositely positioned capillary tips: a) two hexane droplets in water; b) two air bubbles in water; c) hexane droplet (left) and air bubble (right) in water As an example of application, the instrument is used to quantify the stability between protein covered oil droplets in an aqueous medium and to demonstrate how the addition of low molecular surfactants can change the coalescence behavior. References [1] S. Ata, J. Colloid Interface Sci. 338, 558 (2009) [2] G.Loglio, P.Pandolfini, F.Ravera, R.Pugh, A.V.Makievski, A.Javadi and R.Miller, Experimental Observation of Drop-Drop Coalescence in Liquid-Liquid Systems: Instrument Design and Features, in "Bubble and Drop Interfaces", Vol. 2, Progress Colloid Interface Sci., R. Miller and L. Liggieri (Eds.), Brill Publ., Leiden, p. 384, (2011).
DROP AND BUBBLE MICRO MANIPULATOR (DBMM) - A UNIQUE TOOL FOR MIMICKING PROCESSES IN FOAMS AND EMULSIONS
G Loglio;F Ravera;L Liggieri;
2012-01-01
Abstract
The direct interaction between two droplets or two bubbles represents an important elementary process in foams or emulsions. The knowledge about the stability of the film between them is essential to prevent coalescence. There are not many tools known in literature which allow to study this [1]. We present a drop and bubble micro manipulator (DBMM) as a new experimental tool for the quantitative analysis of the interaction between two drops or two bubbles, or even between a single drop and a single bubble, in a liquid medium. For each drop or bubble, a coarse and a very fine dosing system exists in order to control their size or change it in respect to a given protocol. Accurate pressure sensors for each drop/bubble allow to record changes in the capillary pressure and also to detect coalescence [2]. The DBMM also allows to study the stability of liquid films between drops or bubbles under the effect of external perturbations, i.e. a harmonic oscillation with a given frequency and amplitude can be generated in the drops/bubbles in order to find critical conditions for the coalescence. The instrument can be equipped with a fast video camera in order to monitor fast processes such as the coalescence. Situation at the tip of two oppositely positioned capillary tips: a) two hexane droplets in water; b) two air bubbles in water; c) hexane droplet (left) and air bubble (right) in water As an example of application, the instrument is used to quantify the stability between protein covered oil droplets in an aqueous medium and to demonstrate how the addition of low molecular surfactants can change the coalescence behavior. References [1] S. Ata, J. Colloid Interface Sci. 338, 558 (2009) [2] G.Loglio, P.Pandolfini, F.Ravera, R.Pugh, A.V.Makievski, A.Javadi and R.Miller, Experimental Observation of Drop-Drop Coalescence in Liquid-Liquid Systems: Instrument Design and Features, in "Bubble and Drop Interfaces", Vol. 2, Progress Colloid Interface Sci., R. Miller and L. Liggieri (Eds.), Brill Publ., Leiden, p. 384, (2011).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
