Stamp-sized graphene sheets riddled with holes could be boon for molecular separation
MIT engineers have found a way to directly “pinprick” microscopic holes into graphene as the material is grown in the lab. With this technique, they have fabricated relatively large sheets of graphene (“large,” meaning roughly the size of a postage stamp), with pores that could make filtering certain molecules out of solutions vastly more efficient. Such holes would typically be considered unwanted defects, but the MIT team has found that defects in graphene — which consists of a single layer of carbon atoms — can be an advantage in fields such as dialysis. Typically, much thicker polymer membranes are used in laboratories to filter out specific molecules from solution, such as proteins, amino acids, chemicals, and salts. If it could be tailored with pores small enough to let through certain molecules but not others, graphene could substantially improve dialysis membrane technology: The material is incredibly thin, meaning that it would take far...