Dear all,

I have a thin layer of PDMS (30µm thick)  sandwiched between foils of
polycarbonate.  The lower polycarbonate layer has channels of ~25µm depth
and 150µm width. There are interconnects that supplies the fluid to the
channel (water)

I have to prevent the leakage of water. Hence I am clamping the whole system
between two thick  blocks (by means of screws). When I apply a hydrostatic
pressure I could see the water flow in the micro channels and also in the
interconnects.

The main problems are:

(i) If I apply less pressure on the clamping, the water leaks between the
interfaces.

(ii) If I apply more pressure then there is no flow of water in the
microchannels. I suspect this is due to the fact that the PDMS membrane
stretches and also some form of bending occurs (PDMS might bends and block
the channel) that block the flow of water.

(iii) The clamping pressure is not uniform and since it is applied manually
this could also have some implications.

My questions are:

1. Is there is any way that I can make the clamping leak proof and in the
same time have a nice flow (less than 1痞/min).

2. Lot of bonding methods have been presented in the literature. Has anyone
successfully verified bonding of PDMS/ polycarbonate in their own laboratory
settings.

3. Should a thicker PDMS membrane or a fluid such as isoproponal which has
smaller contact angle with water will solve the problem.

Thank you in advance
Allwyn.