How to change, decrease to be specific, the adhesion strength between solidified PDMS and polystyrene microparticles?
Thank you!
Sincerely,
Shuai
I used 1 um PS particles and could significantly reduce the unspecific adhesion by adding homeopathic amounts of Tween 20 (0.05v/v%) and by using carboxy-modified particles (I think this does the trick!).
Apparently, the adhesion would also be reduced when the channel is hydrophillic (so directly after bonding before the hydrophobic recovery) but I have not tested this
Dear both, sorry for jumping into this thread. Actually I am interested in the opposite side of the question. In my recent practice I noticed that the adhesion between PDMS and gold-coated PS beads (1-2 um) is weaker than that between PDMS and bare PS beads. Would it be possible to increase the adhesion (with gold)? Thank you very much in advance.
Hello Kan Yao, thank you for your remark. As i have little experience regarding your question, I would suggest you to buy PS without the gold-coating then. Or you can try surface modification, e.g. plasma treatment of the PDMS, or use some surfactant to coat the PS.
By the way, did you get the gold-coated PS from one supplier or did you coated them yourself? If it is the first case, would you tell me which company you ordered your particles from? Thank you!
Hi Shuaizhong, thanks a lot for the prompt reply. I will give a try with O2 plasma.
Our particles are coated using sputtering and are thus half-coated. If you are interested in making core-shell particles, maybe chemical synthesis could be an option (see, e.g., Langmuir 21, 1610-1617). I once synthesized gold coated silica particles, where the overall flow is pretty much the same with only the surface modification slightly different. The only issue is that micron-sized particles tend to aggregate. I also have some impression there is a supplier providing gold-coated particles (not sure the core is PS or silica) but I have no idea of the quality. I will add the link later once I find it.
Hi Shuaizhong, I recalled the keywords and it should be this one: http://microparticles.de/en/produktpalette#Area29
I don't know why the metal-coated catalog is empty. Maybe you can send them an email or just keep an eye on it.
Another supplier also claim they have coated silica beads (http://www.nanocs.net/nanoparticle/gold-silica-nanoshell.htm), but 2-5 nm sounds not safe for a continuous shell. Just fyi.
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