Fig. 2. (A) DMF GPC curves obtained for a PEG₅₇-PHPMA₁₂₀ diblock copolymer and its corresponding PEG₅₇ macro-CTA (molecular weight data are expressed relative to PEG standards). (B) TEM images and digital photographs for the thermoreversible degelation behavior exhibited by a PEG₅₇-PHPMA₁₂₀ worm gel, which undergoes a worm-to-sphere transition to form a free-flowing liquid when cooled to 4 °C. (C) Storage (G′) and loss moduli (G′′) obtained by oscillatory rheology measurements during a thermal cycle for a 10% w/w aqueous dispersion of PEG₅₇-PHPMA₁₂₀ nano-objects. This thermal cycle involved cooling from 25 °C to 4 °C (at 1 °C intervals) and then returning to 25 °C; data were obtained at an angular frequency of 1.0 rad s⁻¹ at 1.0% strain, with 5 min being allowed for thermal equilibration between each measurement. (D) Representative I(q) vs. q plots recorded for 1.0% w/w aqueous dispersions of as-synthesized PEG₅₇-PHPMA₁₂₀ worms (green circles) at 24 °C, spheres, dimers and trimers (red circles) at 7 °C and reconstituted worms (black circles) at 24 °C. The data fits to the first and last SAXS patterns obtained using a worm-like micelle model are shown in yellow and orange, while the data fit obtained for the middle SAXS pattern utilized a ‘spheres, dimers and trimers’ model. In each case, the low q gradients (approximately −1 for worms and close to zero for spheres, dimers and trimers) are consistent with the corresponding TEM images.