A novel luminescent sensor for disaccharide detection in food: Synthesis and application of a water-soluble rod-coil ionic block copolymer

•The rod-coil ionic block copolymer PF-b-PDI has been used as a novel fluorescence probe.•This probe allowed detecting the disaccharide in food with low detection limit.•This probe was used for the determination of lactose in milk with the low cost.