It's one of those "why didn't I think of that" papers, although in my case, as much as I hated electrochemistry, I have an out.
The researchers used 3-[4-(bromomethyl)phenyl]-3-(trifluoromethyl)-diazirine as their crosslinking agent, due to its formation of free radicals in reductive electrochemistry. Once the free-radicals are formed, then we are in a common realm for polymer chemists and my comfort level returns. Take a look at the mechanism:
One limitation on this technology is pretty obvious - it is restricted to curing between conductive substrates. (Metals, indium-tin oxide coated surfaces such were used here, inherently-conductive polymers...) But what is far more concerning with this particular curing agent is that it generates N2. Gas generation in a polymer matrix is usually not desirable (unless you are making foams). It's only 1 mole per mole of diazirine, so the total amount is limited since crosslinking agents are seldom used at high levels. But still...
I recognize well that initial discoveries are seldom without issues, so consider this criticism of the nitrogen generation as a setting a direction for the mandatory "future research". But since it will involve electrochemistry, feel free to go ahead without me.
[*] That expression being "There's more than one way to skin a cat". The origins of it aren't entirely clear from what I can find online, but the meaning is: there's more than one way to get a job done. Despite the literal reading of the expression being quite gruesome, it is quite commonly said indicating that no literal intent is intended.
2 comments:
Dear John,
Greetings from a fellow Minnesotan. And thanks for disseminating our research. N2 gas generation may only be a problem depending on how fast you activate the diazirines, matrix solubility, and diffusion rates. Turns out N2 is pretty soluble in a lot of matrices (e.g. Guinness Beer and deep sea divers) and doesn't gas nucleate so quickly--allowing time to diffuse before foaming.
Dont be afraid of the electrochemistry--turns out it's a more elegant method of controlling reduction and oxidation potentials.
Please be on the look out of our forthcoming photo-bioadhesive hydrogels manuscript, fully characterized by real-time dynamic rheometry.
Sincerely,
Terry
@Terry,
Good convincing argument on the N2, and I look forward to the new manuscript. Please feel free to alert me to it.
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