Begin by cutting the methylmethacrylate or MMA coated graphene squares into grid sized pieces. To do so, use two sets of reverse action forceps to support the CVD graphene square, while ensuring the MMA side faces up while attaching it to the forceps. To cut the graphene into small squares, use the two sets of reverse action forceps to hold the graphene right side up, anchoring it in position, as well as to hold the edge of the small square after cutting it away from the rest of the big square.
Tilt the beaker containing ammonium per sulfate, or APS, to place the squares in it at a shallow angle without sinking. Then pick a square and make it contact the surface of the APS solution before releasing it. After covering the beaker with aluminum foil, incubate it overnight at 25 degrees Celsius.
Next, to remove the MMA graphene films from the APS solution, first, plunge a glass cover slip vertically into the solution and then move it laterally such that it touches a floating square. Then carefully remove the cover slip while ensuring that the film adheres completely to the side of the cover slip upon removal. Plunge the cover slip vertically into molecular grade water in a 50 milliliter beaker to dislodge the attached film into the water.
In a similar manner, transfer all the films to the beaker. Let the films remain in the beaker for 20 minutes before they are ready to be adhered to cryo EM grids.
