Preparation characteristics of oil-in-water emulsions using differently charged surfactants in straight-through microchannel emulsification

CFD analysis of microchannel emulsification: Droplet generation process and size effect of asymmetric straight flow-through microchannels

“…The resultant droplet size is primarily determined by the dimensions of the MC array (Sugiura et al 2002a). The droplet size and its distribution are barely influenced by the velocity of each phase below a critical value (Sugiura et al 2002b;Kobayashi et al 2003), indicating that MC emulsification is useful for practical production of monodisperse emulsions. Moreover, straight flow-through MC arrays are promising for mass production of uniform droplets, since numerous channels (e.g., 10 4 cm -2 ) can be compactly arranged on an MC emulsification device (Kobayashi et al 2002a;2005a).…”

The impact of mass transfer and interfacial expansion rate on droplet size in membrane emulsification processes

“…Several studies have found that there is an upper limit of dispersed phase flux at which the droplet size begins to increase under the same cross-flow conditions [9,10,23]. If the dispersed phase flux is further increased, the average droplet size begins to escalate and the coefficient of variation can increase by 10-20-fold [9,11]. From the above-mentioned analysis it can be justified that changes in the interfacial tension are the most likely and dominating phenomena causing the cross-over between different modes of droplet formation.…”

“…For extensive and recent reviews on membrane emulsification consult Joscelyne and Trägårdh [4], Charcosset et al [5] and Gijsbertsen-Abrahamse et al [7]. Other authors have described droplet formation depending by considering the type of mechanisms causing the droplets to detach and or the systems sensitivity to operating conditions [8][9][10]. There are two main detachment mechanisms described in the literature: spontaneous transformation-based (STB) droplet formation and, shear induced droplet formation.…”

Generation of highly uniform droplets using asymmetric microchannels fabricated on a single crystal silicon plate: Effect of emulsifier and oil types

“…The mean droplet/channel size ratio of 2.63 was smaller than the mean droplet/pore size ratio of 3.0 found in droplet formation from Shirasu Porous Glass (SPG) membrane within the same range of SDS concentration [32], but similar to the mean droplet/pore size ratios in membrane emulsification using asymmetric aluminium oxide membranes [33,34]. The d 3,2 value of 26.3 m is significantly smaller than the average droplet diameter of 39.1 m reported in straight-through MC emulsification for the system containing 1 wt% SDS and soybean oil using a symmetric MC plate with 10  50 m channels [25]. In the case of symmetric channels a growing droplet retain a spherical shape during droplet formation process with an ellipsoidal or circular neck inside the channel [35], whereas in the case of asymmetric channels, a growing droplet is deformed inside a microslot into an ellipsoidal disc-like shape which is energetically highly unfavorable.…”

“…either rectangular ( Fig. 1(a)) or circular (Fig 1(b)) [23,[25][26][27]. According to Kobayashi et al [28], rectangular microslots provide better droplet monodispersity than circular microchannels and a slot aspect ratio (length/width ratio) should be higher than 3 to obtain monodisperse droplets with a coefficient of variation smaller than 2 %.…”