Polyacrylonitrile (PAN) was synthesized and grafted from silicon wafers by copper-mediated photoinduced atom transfer radical polymerization (ATRP) using α-bromophenyl acetic acid-based initiators. Aggregation-induced photonic emission (AIE) was observed in well-defined, low molecular weight (M n < 10k) bulk PAN as well as in thin (d < 15 nm), surface-grafted polymer brushes. † Electronic supplementary information (ESI) available. See