Formation of nanoemulsions in stirred media mills

Alkane-Tween85-water-systems have been used as model emulsion systems to demonstrate the feasibility of emulsification in stirred media mills. The influence of fundamental process parameters, le. emulsion formulation (oil mass fraction and oil-to-emulsifier mass ratio), stress conditions (grinding bead size and stirrer Lip speed), process Lime and especially temperature on the emulsion droplet size and size distribution has been studied for this approach. By lowering the process temperature below the solidification temperature of the oil phase, coalescence and ripening can be significantly reduced. Smallest product droplets with x(1,2) < 10 nm thus are obtained even for nominal oil mass fractions up to 20 wt% in the hexadecanc-Tween85-water system. The feasibility of the process proposed to produce nanoscale emulsions using oil phases loaded with compounds such as pigments and other fillers is demonstrated. (C) 2013 Elsevier Ltd. All rights reserved