Polyamide 6 (PA6) nanofibres prepared by electrospinning were plasma treated using a microwave surface-wave jet at atmospheric pressure. The exposition to the plasma induced chemical and morphological changes of the nanofibre mats. The apparent porosity observable in SEM images was found to depend on the duration of plasma treatment. The ATR-FTIR and XPS detected increase of oxidised functional groups on the surface was consistent with kinetic model developed. The plasma treatment was compared to thermal treatment, which induced the morphological but not chemical changes of the fibres. (C) 2014 Elsevier Ltd. All rights reserved.