It's been fire polished according to the website. It might not have enough silanols on the surface. Check the contact angle. Use UV/ozone or laser until it gets more hydrophilic by contact angle. I'm curious what the research project is; why don't you PM me?

OK we have RIE for O2 plasma, I will try before thermal fusion, we are working with microfluidics, we have good results bonding PDMS to Glass but we are trying glass-glass to obtain a more robust chip.

Many thanks for the tip

Fire polishing generates a.very smooth surface. I think you need silanols based on reading although I have not done t experiments myself. I might try roughening the sample using sandpaper on water, too. Also, check what the annealing temperature of your composition is.

I succeeded in bonding but air bubbles appears, I am trying with plasma today.

Did air bubbles appear before or after the bonding? You are probably creating a solution that is too viscous. You should try raising the bonding temperature slightly. Or adding a fining agent (like salt) if it'll mix, although note it will incorporate itself into the structure.

the air bubbles appear after bonding, the picture was the try at 600°C degrees. The annealing temperature acording to the data sheet is 541°C. I am trying with 620°C at this moment, and we perform a functionalization with O2 plasma but it should bound together after plasma? because I could not feel bonding after plasma treatment between glass slides, despite of thath I put it into the oven.

Many thanks for your time and support

Hey,

Below is one reference on the topic. I know there are a few others online that I recall reading. I recommend comparing procedures and seeing what they have in common. My suggestions have been based on the idea that hydroxyl formation is needed before some of these procedures.

R. Marie, J. P. Beech, V. Janos, J. O. Tegenfeldt, and F. Höök, “Use of PLL- g -PEG in Micro-Fluidic Devices for Localizing Selective and Specific Protein Binding,” Langmuir, vol. 22, no. 24, pp. 10103–10108, 2006.

If that doesn't help... Based on what you are saying, I think you might want to ask yourself what the bubbles are and why they are forming. Look at where they are and when they occur. Ask yourself, (1) Are these bubbles trapped air, coming from the atmosphere, or are they bubbles (perhaps water vapor) that result from the bonding process? (2) If they are water vapor, did they form from condensation with the polymer and could I make the surface have fewer hydroxyl groups to limit condensation? If you measure the contact angle or water region in IR prior to bonding, you can correlate that with hydroxyl concentration and see if the hydoxyl concentration is related to bubble formation. (3) If the bubbles are from air, are they present in the glass prior to bonding or after bonding? If bubbles weren't present in the glass or that the polymer precursor wasn't stirred in such a way to incorporate air, why would the bubbles be at the polymer/glass interface; is there some explanation in terms of surface energies?

Ok many thanks, I will check the literature and keep you actualized in advance, we are near to achieve it.

I want to thank you Prof. Elizabeth I Morin because of your very useful advice and time you expend to answer my question, I checked the literature you give to me and your tips, we finally achieve glass-glass bonding and this is how we achieve it, this maybe be usseful for you and is my way to thanks your effort.

First, the glass composition is not in the provider web page but can be found here "http://www.ingentaconnect.com/content/sgt/pcg/1998/00000039/00000002/3902101"

and here

"https://www.google.ch/patents/US6441809"

We could not achieve bonding with the procedure from Pan Mao at 541°C (Annealing point), but we achieve bonding this way.

After exhaustive cleaning with RCA proccess the glass was dried overnitght at 40°C to avoid humidity and then joint together and heated at 620°C 5h. Another way was this; after cleaning we use a very thin layer of Cr of about 50nm and then oxidized with O2 plasma, after that, we put together both glasses and then heated at 600°C for 5h.

Other thechnique was using weight, after cleaning and drying the glass we put toghether the glasses and then pressed with weight between to steel layers of about 1cm widht and 10x10cm of area and using less temperature not 600°C.

In all cases the surfaces in contact with glass must be flat and clean because every little imperfection in contact with the glass surface is replicated and we should avoid humidity in all cases.

Again many thanks for your sugestions, one issue was humidity as you told me. If you are interested in this proyect you can feel free to contact me at any time and I will try to give to you my best answers.