Recently, our lab has had difficulty with PDMS bonding to glass after plasma treatment (air, not O2) after months of no issues. We have just come out of a dry winter, and I hypothesize that higher humidity levels are interfering with the bonding process. Has anyone had similar issues in the past?
Are you sure it is the same glass? same supplier, same composition, same cleaning procedure? How long do you store plasma-treated substrates before coating?
All reagents are the same. After plasma treatment, pdms is placed directly onto the glass for bonding (
Hi,
The relative humidity is of influence of the formed, and later active -OH sites. As you perform plasma with ambient air, in a dry period, less water is in the plasma. Water plasma is very effective in forming -OH groups.
Also during the time from plasma to bonding, the PDMS will recover the hydrophobic nature. In a dry environment this will go faster than in a wet environment.
And the glass surface will also have more available hydroxyl groups which can bond when it is cleaned and more ambient water is available.
Hope this helps,
Marc
Hi James, your surfaces should be dried before you put them into the chamber, and they are pumped down further to make the plasma. I don't think the ambient water is affecting the subsequent bonding, but have you tried placing the bonded devices at elevated temperature 65-80C as this strengthens the bond? You may also have to optimize your plasma activation time.
About poly(dimethylsiloxane) (PDMS) bonding, you may want to see: J. Micromech. Microeng. 18 (2008) 067001; http://iopscience.iop.org/article/10.1088/0960-1317/18/6/067001/meta
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Carbon Materials
- Graphite
- Graphene