Fig. 3. (A) Reaction scheme for the selective removal of the trithiocarbonate-based RAFT end-group from a PEG₅₇-PHPMA₆₅ diblock copolymer in an ethanol/water mixture by reaction with a twenty-fold excess of AIBN initiator (relative to the number of moles of end-groups). (B and C) GPC data recorded for this PEG₅₇-PHPMA₆₅ diblock copolymer using either a refractive index detector or a UV detector (λ = 298 nm). Analysis of the latter chromatograms suggests that 98% of the trithiocarbonate end-groups were removed. (D) Digital photographs recorded for as-synthesized and AIBN-treated PEG₅₇-PHPMA₆₅ powders indicate a subtle colour change from pale yellow to white after end-group removal. (E) Storage (G′) and loss moduli (G′′) obtained by oscillatory rheology during a 4 °C to 37 °C to 4 °C thermal cycle for a 12% w/w aqueous dispersion of PEG₅₇-PHPMA₆₅ nano-objects redispersed in a commercial cell culture medium (Nutristem). These data were obtained at 1 °C intervals using an angular frequency of 1.0 rad s⁻¹ at an applied strain of 1.0%, allowing 2 min for thermal equilibration prior to each measurement.