Grafting well-defined CO2-responsive polymers to cellulose nanocrystals via nitroxide-mediated polymerisation: effect of graft density and molecular weight on dispersion behaviourElectronic supplementary information (ESI) available: 1H NMR spectra and GPC chromatograms for P(DEAEMA-co-S)-SG1 and P(DMAPMAm-co-S)-SG1 macro-alkoxyamines, GPC chromatograms of chain extended macroalkoxyamines, 1H NMR spectrum of a CNC-GMA dispersion, calculation of total amine groups on the CNC surface, AFM images of

A grafting to approach on a cellulose derivative using reversible deactivation radical polymerisation (RDRP) is reported for the first time. SG1-capped poly( N , N -(diethylamino)ethyl methacrylate) (PDEAEMA) and poly( N -3-(dimethylamino) propyl methacrylamide) (PDMAPMAm) macroalkoxyamines of different molecular weights, showing low dispersity, high livingness and end group fidelity were grown in bulk through Nitroxide-Mediated Polymerisation (NMP) using the alkoxyamine N -hydroxysuccinimidyl BlocBuilder® (NHS-BlocBuilder). In the second step, these CO 2 -responsive macroalkoxyamines were grafted to glycidyl methacrylate (GMA) modified cellulose nanocrystals (CNC) to obtain CO 2 -responsive CNC. Two different tertiary amine polymers were selected to investigate how differences in their p K aH and T g affected the final properties of the graft-modified CNC. The effect of the macroalkoxyamines molecular weight on the graft density was investigated in detail and was shown to have a direct influence on the dispersion behaviour and CO 2 -responsiveness of the grafted CNC particles, as demonstrated by zeta potential measurements in water and phase shuttling experiments between oil and water. The results suggested that a particular p K aH , minimum graft density and graft length are required to effectively switch the CNC from a hydrophilic to a fully hydrophobic state. Tertiary polyamines and polyamides were grafted to cellulose nanocrystals (CNC) via Nitroxide-Mediated Polymerisation to yield well-defined CNC, which were examined for their CO 2 -responsive dispersibility in water and oil.