Table 2.
Summary of clay mineral behavior in 15%/15% w/w PEG/Dx ATPS.
| Clay Type | Partitioning in bulk ATPS | Interaction with labeled polymer | Microscale distribution in ATPS | Droplet stabilization? |
|---|---|---|---|---|
| Kaolinite (KGa-2) | Dx-rich phase | Dx | Primarily at the interface with some in Dx-rich phase | Yes (droplets eventually sediment but do not coalesce) |
| Na-rich Montmorillonite (SWy-2) | no clear preference | —a | Interface and PEG-rich phase | No |
| Ca-rich Montmorillonite (STx-1b) | PEG-rich phase | —a | Interface and PEG-rich phase | Nob |
| Illite (NX-illite) | Dx-rich phase | Dx | Interface | Yes (droplets eventually sediment but do not coalesce) |
aNo apparent adsorption of either labeled polymer to majority of particles in these samples. Non-montmorillonite impurity particles in these samples interact with labeled dextran; see text and Supporting Information for discussion.
bCa montmorillonite particles in PEG-rich phase sometimes physically block contact of Dx-rich droplets; they do not accumulate at or stabilize the interface.