Assembly of nanoparticles-polyelectrolyte complexes in nanofiber cellulose structures

•We quantify the effect of cationic polyacrylamide (CPAM) dosage on the assembly of silica nanoparticles (NPs) within a nanocellulose composite.•Increasing CPAM dosage increases retention of NPs within the cellulose matrix with stronger interparticle interactions.•Small angle X-ray scattering (SAXS) and microscopic reveal that CPAM concentration affects the aggregates size of SiO2 NPs within the composite.•We show a bimodal distribution of spherical particles (8–20 nm in diameter) in nanocellulose composites by modelling the SAXS curves.•Data analysis allow understanding interparticle interactions within assemblies of SiO2 NPs at the nanometer scale with different dosage of CPAM.