PMID- 23123671
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20130425
LR  - 20121119
IS  - 1473-0189 (Electronic)
IS  - 1473-0189 (Linking)
VI  - 12
IP  - 24
DP  - 2012 Dec 21
TI  - Microfluidic synthesis of atto-liter scale double emulsions toward ultrafine 
      hollow silica spheres with hierarchical pore networks.
PG  - 5262-71
LID - 10.1039/c2lc40886d [doi]
AB  - A facile PDMS-glass hybrid microfluidic device is developed for generating 
      uniform submicrometer-scale double emulsion droplets with unprecedented 
      simplicity and controllability. Compared with planar flow-focusing geometries, 
      our three-dimensional flow-focusing geometry is advantageous for stably producing 
      femto- to atto-liter droplets without the retraction problem of the dispersed 
      phase fluid. In addition, this microfluidic platform can withstand the use of 
      strong organic solvents (e.g. tetrahydrofuran (THF) and toluene) as a dispersed 
      phase without deforming PDMS devices because the dispersed phase containing 
      organic solvents does not directly contact the PDMS wall. In particular, 
      monodisperse double emulsions are generated spontaneously via the internal phase 
      separation of single emulsions driven by the diffusion of a co-solvent 
      (tetrahydrofuran) in microfluidic devices. Finally, we demonstrated that the 
      double emulsions can be used as morphological templates of ultrafine spherical 
      silica capsules with controlled hierarchical pore networks via the 
      evaporation-induced self-assembly (EISA) method. During EISA, triblock copolymers 
      (Pluronic F127) act as a surfactant barrier separating the internal droplet from 
      the continuous oil phase, resulting in the 'inverse' morphology (i.e. hydrophobic 
      polymer-in-water-in-oil emulsions). Depending on the precursor composition and 
      kinetic condition, various structural and morphological features, such as 
      mesoporous hollow silica spheres with a single central core, multi-cores, or a 
      combination of these with robust controllability can be seen. Electron microscopy 
      (SEM, STEM, HR-TEM), small angle X-ray scattering (SAXS), and N(2) 
      adsorption-desorption confirm the well-controlled hierarchical pore structure of 
      the resulting particles.
FAU - Jeong, Woong-Chan
AU  - Jeong WC
AD  - Department of Chemical and Biomolecular Engineering, KAIST, Daejoen, 305-701, 
      Korea.
FAU - Choi, Minkee
AU  - Choi M
FAU - Lim, Che Ho
AU  - Lim CH
FAU - Yang, Seung-Man
AU  - Yang SM
LA  - eng
PT  - Journal Article
PL  - England
TA  - Lab Chip
JT  - Lab on a chip
JID - 101128948
EDAT- 2012/11/06 06:00
MHDA- 2012/11/06 06:01
CRDT- 2012/11/06 06:00
PHST- 2012/11/06 06:00 [entrez]
PHST- 2012/11/06 06:00 [pubmed]
PHST- 2012/11/06 06:01 [medline]
AID - 10.1039/c2lc40886d [doi]
PST - ppublish
SO  - Lab Chip. 2012 Dec 21;12(24):5262-71. doi: 10.1039/c2lc40886d.