Formation of nanostructured cellulose stearoyl esters via nanoprecipitation†
Nanoparticles (NPs) from derivatives of native polysaccharides have not been as intensively studied yet as those from synthetic polymers. In this report, NPs in aqueous suspensions were fabricated using cellulose stearoyl esters (CSEs) with different molecular weights via nanoprecipitation using dropping and dialysis techniques. The average diameters of NPs depended strongly on the concentrations of CSE solutions, molecular weights of CSE and also the nanoprecipitation technique. Both nanoprecipitation techniques are based on different mechanisms and NPs from dialysis are generally larger than NPs from dropping. The mechanism for dropping nanoprecipitation was further analyzed based on the properties of NPs which contain crystallized stearoyl groups in CSE chains. The average diameters of freshly-prepared CSE nanoparticles decreased with rising temperature, which is accompanied by the release of THF from the interior of NPs. The intensity of the size reduction of up to 35% depended on the one hand on the concentration of CSE solutions, and on the other hand on the molecular weights of CSEs. Finally, it was shown that these NPs can be used for the fabrication of temperature-responsive superhydrophobic surfaces.