Tagged: sugru

Sugru in a chemistry lab



Screaming voice from the back of the room: “What the hell is sugru????”. Sugru, my dear friend is an amazing material that has millions, if not billions, different applications, from preparing old stuff to hack new stuff. Their website has nice videos about it.

Screaming voice from the back of the room: “I’m in my lab, why the hell should I care???”. You see, my dear friends, sugru can help a lot also in a standard chemistry lab, and this chemistry world blogpost is a clear example.

Screaming voice from the back of the room: “Oh my God, that’s pretty impressive, I’m out for buying 10kg of it”. Ok, ok, ok, now relax a little bit and think about the video. What if you modify your glassware with sugru and then during your nice DCM column sugru becomes sticky leaving a forrest of peaks in your NMR spectra?

There is almost no data on the amazing material (no, i din’t get paid from sugru) stability to organic solvents. So in my spare time I decided to do some experiments on it.

First of all, as most of the amazing plastic materials down here, sugru principal component is PDMS (yep, the same  stuff of microfluidic devices,  breast implants, crappy food and naturally silly putty). How do I know it? Well, it’s not a secret, you can find the patents here, here and here. Now, if you tell me “PDMS”, the first thing that come up in my mind is “swelling”.

Let’s try to swell some sugru in organic solvents then. I used a standard pack of blue sugru, let it cure for 24h in air, cut it in small pieces and then left it in various organic solvents for 12h. Then I measured again the length and the weight.


Swelling of sugru in different organic solvents
Swelling of sugru in different organic solvents

First of all, and extremely good point, the dye was not leaking in any of the solvents tested. This means that either the dye is covalently linked in the silicon polymer or in huge particles.

As kind of expected, the swelling of sugru is practically identical to the one of cross linked PDMS (classic paper from Whitesides here). Swelling(S)= D/D0 where D is the length of sugru in the solvent and D0 is the length of the dry sugru.

Complitely stable in water, water/HCl and Water/NaOH (S=1 for all the three), in Acetone (S= 1.03), Methanol (S=1.01) and DMSO (S=1.05)
Moderate swelling in DCM (S=1.15), EtOAc (S=1.20)
High swelling in Toluene (S=1.35), Hexane (S=1.40), DMF (S=1.42) and TEA (S=1.62).
The sample in EtOAc, Hexane and TEA were also extremely brittle.

So, depending by how you want to use sugru, and how long it will be in contact with organic solvents I would avoid the high swelling ones….

Now, the second things that comes up in my mind when you say “PDMS” is……. “Surface modification”….

Also in this case, sugru act like PDMS, 20 seconds in the plasma oxygen oven and the groups on the surfaces are beautiful hydroxyls, ready for other amazing reaction on surfaces….

Surface modification of sugru
Surface modification of sugru

I was naturally too lazy to check the contact angle, but I think is pretty evident :)

For now that’s it, another amazing material in the DIY chemistry toolbox. Stay tuned for more use of sugru in a chemistry lab.