Dopamine-induced functionalization of cellulose nanocrystals with polyethylene glycol towards poly( L -lactic acid) bionanocomposites for green packaging.

•Dopamine-induced functionalization of CNCs with PEG in aqueous media is proposed.•PEGgCNCs significantly enhance the crystallization of PLLA.•Mechanical properties of the composites can be tailored by the length of PEG chains.•Great improvement in gas barrier properties of PLLA films is achieved.