Thermodynamic investigation of nanoplastic aggregation in aquatic environments

•Aggregation of nanoplastics (NPs) was studied by ITC and time-resolved DLS.•Homoaggregation of NPs in different electrolyte solutions was all entropy-driven.•Change in the entropic contribution in NP heteroaggregation depended on salt type.•Heteroaggregation of NP and hematite was governed by DLVO and non-DLVO forces.