[3dem] Weird droplets

[Bill & Sue Tivol]

> On Oct 19, 2016, at 6:30 AM, Sergej Masich <Sergej.Masich at ki.se> wrote:
> 
> Dear List,
> 
> I probably missed the discussion since many of you had observed this phenomenon I suppose (see attached images). This is a Quantifoil grid with additional continuous layer of thin (5 nm) carbon. The grid was glow-discharged during 120 seconds, the solution was applied to the “proper” side (facing grid-box centre), blotted and plunge-frozen in liquid ethane. Why do these droplets form? I do not see the droplets after applying solution to the opposite side of the grid. Shouldn’t the carbon surface inside the holes be homogeneously hydrophilic? The surface outside the holes seems to be completely hydrophobic. Is it due to residual plastic?
> 
> Thank you in advance.
> 
> Sergej
> 
Dear Sergej,
	I do not know what the droplets are, but I have had experience with residual plastic on Quantifoils.  For a while about a decade ago, the quality of Qfoils was not particularly good, but they offered foils that were cleaner (for a fee, of course).  We found that C-flat grids had better quality control.
						Yours,
						Bill