Hello all..
Right now I am working on the triblock copolymer (ABA) system. Triblock copolymer contains Poly(styrene-Isoprene-Styrene) in this i want to remove anyone of the block either isoprene or styrene . Can anyone suggest me how to remove block from ABA?
Thank you..
The solvent/non-solvent profile for both polymers is quite similar which makes it hard to separate these polymers by precipitation. n-Hexane at room temperature is a selective solvent for polyisoprene (http://pubs.acs.org/doi/abs/10.1021/ma100428a.), but PI-containing diblock and triblock copolymers could form core-shell nanostructures, leading to loss of product.
I would suggest that you try column chromatography.
Perhaps your question is ill phrased, but you seem to be saying that you have an ABA block copolymer, and you want to remove one of the blocks, either A or B. What do you think you would have afterwards? Or are you saying that there are AA or BB contaminants that you want to remove?
I assume you would like to remove homo PS or homo PI from the block copolymer.
Question : which amounts would you like to purify?
If the amounts are small enough, chromatography might be suited.
Either prep. SEC (Separation by size, depends on the molar masses of the blocks)
Alternatively chromatography at critical conditions of adsorption LCCC will be the method of choice. Check literature of Taihyun Chang and/or Harald Pasch.
Dear Radke,
Block copolymer (BCP) is not in bulk, BCP coated on silicon wafer its around 190 nm Thin film, From the thin film i have to remove either Isoprene or Styrene unit for lithography study. I would like to know the process on degradation/removal of BCP unit.
You really need to rethink the approach. You may well need first to design the polymer so you can do selective degradation, and then figure out how to coat with it. For example, a polyamide or polyester instead of polyisoprene, properly chosen, might be degraded an acidic water wash. leaving polytyrene behind.
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