Help spec'ing elastomer for microfluidic application 1

[fikst]

Hi all,

I'm new to the forums here but I was hoping to get some help finding an elastomer that will work for our application. The material will be part of a microfluidic device and needs the following properties:

Soft - We need to be able to collapse tiny channels in the device with a plastic roller
Wear resistant - The channels will be repeatedly collapsed and expanded by a rotating mechanical system. The material will need to hold up to wear from the rotating parts.
Bio-compatbile - The material cannot be poisonous to cells
Bondable - We need to be able to attach two sheets of elastomer through some bonding method (could be solvent or plasma based, we are trying to stay away from adhesives if possible)
Low gas permeability

Ideally the material would also be clear but that is not a requirement. In the past we have experiment with PDMS and SEBS. The PDMS gave us issues with bonding and gas permeability and the SEBS ended up wearing far too quickly. I apologize for being a bit vague but the product itself is proprietary. Also, I know that these requirements are a bit conflicting and we would be open to the using some kind of multi-layer setup if necessary. Any help would be appreciated!

Thanks!

 

[johnnymat]

This sounds like some form of micro peristaltic pump action. Definately need to consider some compromises.If it needs to be biocompatible probably requiring some FDA or USP compliance then this will eliminate many traditional wear resistant and easily bondable materials. PTFE is the main material used in these applications , but this is very difficult to bond to reliably.The elastomers that are likely to be useable and biocompatible and available in translucent form would be Fluoroelastomers FKM or FFKM but these cannot be easily softened in the traditional rubber compounding manner and therfore have a limiting hardness of about 65 IRHD. Permeability is not bad ( depends on the gas) and wear is not too bad.

EPDM are a possibility, they can be softer, FDA and USP grades available, bonding pretty good, can be made to be wear resistant but this may compromise Bio compatibility
Johnnymat

 

[tom1953]

Maybe polyurethane? I know there are PU materials used in medical applications, and they have good abrasion resistance and generally pretty good for permeability resistance.

 

[fikst]

Thanks for the help guys! I'll definitely take all of your advice into account as I continue searching. If I come across anything interesting while prototyping I'll be sure to post it.