HI,

even i have a similar problem. but its not because of higher concentration
of dye, but because i use polyelectrolyte marked with rhodamine B. If anyone
has replied to this please let me also know about it.

thanks a lot in advance,
supriya.

On 3/30/06, Vishwanath Somashekar  wrote:
>
> Hi,
> I am using a very high concentration of rhodamine 6g dye relative to a
> couple of papers that I have read about the concentrations that have
> been used to make flow visualization.
>
> My concentration is about 0.5g/L
>
> Since Rhodamine 6g is not soluble in water, I initially dissolve the
> dye with ethanol and then add water.
>
> When I pass this thru the microchannel using 3 streams Left, Right and
> middle.
>
> the left and the right streams contain dye mixed with water and the
> middle one contains just pure water.
>
> The Channel is made of PDMS, which is bonded to glass slide using
> plasma cleaner.
>
> I notice that there are some particles that start to accumalate along
> the channel, which is in contact with the dye streams. I can flush it
> with ethanol, but my purpose is not solved as these particles are
> visible right away and are stuck to the channel. Is there any solution
> to problem?