Production Techniques

Robert Murray-Smith. 2019. Graphene by the Ton. Video. Retrieved from youtube.com/watch?v=7_3cs7NfAuA. (Member-only video)

In this video, a technique for the large-scale (for a private lab) production of graphene is presented. A vertical ball mill, made from the motor and gear assembly of a cordless drill, a plastic (food) beater / whisk head, and a beaker is filled with 1cm diameter glass marbles, to which vegetable glycerine (aka glycerol) and graphite are added. (To allow this apparatus to run unsupervised for a longer period of time, a thermal cut-out switch is mounted to the motor's body.)

In contrast to your typical horizontal ball mill (which is a high-impact, low-shear machine), the vertical arrangement of this mill gives us a no-impact, low-shear machine which, when combined with a sticky substance such as glycerine, approximates the 'adhesive tape-on-graphite' method of exfoliation first developed in the mid 2000s.

The actual mix used is a 1:2 molar mix of glycerine to urea (the latter dissolved into the former at approx. 60°C); the urea is added to prevent the resulting graphene from agglomerating, plus it increases the viscosity of the liquid. For every 250mL of (pure) glycerine, add a few grams of graphite, and let the mill run for approx. 24 hours. The resulting mixture remains 'stable' for many months (i.e. the graphene doesn't settle or drop out of suspension).

Since both are water-soluble, the mixture can be washed, as and when needed, to leave just the graphene, or the resulting glycerine–graphene mix can be used as a plasticiser, e.g., as per Murray-Smith (2020).

From 6:46–7:30, “there is no real restriction on the size — it works very well at 45–150um graphite, but you can go up to 1 or 2mm if you want; I have done 1mm graphite in there so you get very large flakes. Because it's no impact — it's just shear — that flake size is maintained. If you put it in a ball mill, what will happen is it will smash and break the flakes up, as happens on occasion. With this one, because it's just low shear continually, it just peels it off, peels it off, peels it off, and you end up with large flakes in high concentration, in a harmless liquid that you can wash off easily. And really, I don't know what else anybody would want from a graphene-production method.”

Robert Murray-Smith. 2014. Step by Step Method for Making Graphene. Video. Retrieved from youtube.com/watch?v=TLaghpuB1Es.

In this older video, a step-by-step guide to the production of graphene using a water–acetone solvent is presented.

Robert Murray-Smith. 2020. Making Graphene Foam from Table Sugar. Video. Retrieved from youtube.com/watch?v=hKoXk9s2LI8

See also 'blown sugar graphene' on Google Scholar.