Preparation of hierarchical PCFs
Block copolymer–based porous carbon fibers
Sci Adv, Feb 1, 2019; DOI: 10.1126/sciadv.aau6852

PAN-b-PMMA block copolymer was dissolved in DMF at a concentration of 14 weight %. The solution was stirred at 65°C for 2 hours and then electrospun to polymer fiber mats at a feeding rate of 1.5 ml/hour under a voltage of 18 kV (Acopian Technical Company, Easton, PA). The polymer fibers were collected on an in-house–built rotary Al disc. After electrospinning, the fiber mat was peeled off from the collector and dried in a vacuum oven at 60°C for 6 hours. Oxidation and pyrolysis of fibers were conducted in a tube furnace (Lindberg/Blue M, Asheville, NC). The fiber mat was first oxidized by heating from room temperature to 280°C at a rate of 1°C min−1 and kept at 280°C for 8 hours in air. After oxidation, the fiber mat was heated again from room temperature to 800°C at a rate of 10°C min−1, followed by carbonization at the same temperature for 1 hour in a N2 flow (200 standard cubic centimeters per minute). For comparison, pure PAN and a polymer blend of PAN and PMMA (denoted as PAN/PMMA; 64 volume % of PAN) were electrospun into polymer fiber mats and underwent the identical pyrolysis steps at 800°C to obtain carbon fiber mats.