Polydispersity of copolymer lengths or gradient widths in synthesized gradient copolymers is almost inevitable and it can be utilized to tune the interfacial properties. Compared with the monodisperse counterparts, fewer amounts of gradient copolymers are required to saturate a given interfacial area, when gradient copolymers with a polydispersity of gradient widths are used. This arises from small overlap content between chain conformations of bidisperse gradient copolymers on the interfacial monolayer. In contrast, like the bidisperse diblock copolymers increasing the polydispersity of chain lengths in bidisperse gradient copolymers reduces the averaged projection area taken by each copolymer, thus more amounts of copolymers are needed to saturate a given interfacial area. Nevertheless, for the copolymers with polydispersity of chain lengths or gradient widths, the bending modulus is always smaller than the corresponding monodisperse counterparts. Thus mixing gradient copolymers with a gradient width disparity provides a novel route of achieving the saturated (tensionless) interface with fewer amounts of copolymers and of high flexibility. (C) 2015 Elsevier Ltd. All rights reserved.