Again, the degradation was quantified in terms of reduction in molar mass measured via SEC (Figure , S5, and Table ). In most cases, similar reductions in molar mass were observed using L-cysteine compared with both iPrNH 2 and NaOH (see entries 2-4 and 9 in Table ) -this degradation is superior to that observed for the previously studied P(I-co-DOT) copolymers under the same conditions. However, poor solubility of some samples was observed in the 10 mM aqueous cysteine solution, mainly sample 6 (Table ), corresponding to a lesser reduction in M w (44% compared to 74% and 78%). The reduced solubility of sample 6 was thought to be caused by the absorption of the zwitterionic L-cysteine along the copolymer chain, a phenomenon that has been shown to occur in salt solutions. Despite the effect on solubility, L-cysteine has been shown to be a suitable physiological compound that can significantly reduce the copolymer molar mass through disruption of the thioester bonds. Finally, degradation of the DOT-copolymers by a commerciallyavailable household bleach was assessed (Figure ). The bleach was found to cleave the thioester bonds in the copolymer extremely efficiently, significantly reducing their molar mass (up to 76% reduction in M w , Table ). These results demonstrate how easily these hydrophilic copolymers can be degraded using simple commercial products. Since a change in solubility was observed for these copolymers in 10 mM cysteine solution, the copolymer solubility was examined in 10 mM NaCl(aq) solution. Specifically, under these conditions, the derived count rate (DCR) and Z-average diameter (ave) were measured by DLS at different temperatures to assess the upper-critical solution temperature (UCST) behaviour of these copolymers (Figure and Figure ). A dilute solution of copolymer 4 displayed a low DCR (c.a. 1000 kpcs) and a small Z-ave (c.a. 20 nm) at 50°C (Figure ), indicating that the copolymers are fully dissolved and do not form multi-chain aggregates. Both the DCR and Z-ave remained relatively constant between 50°C and 10°C. However, a significant increase in DCR (c.a. 60,000 kpcs) and Z-ave (c.a., 120 nm) was observed at 5°C, indicating the formation of larger aggregates due to a reduction in copolymer solubility (Figure ). Notably, no increase in the DCR was observed in the absence of salt (Figure ). This UCST behaviour is a consequence of the increased hydrophobicity due to the DOT moieties along the copolymer chain and absorption of salt ions onto the copolymer. Similar experiments were performed on copolymers 3 and 6 (Figure ). A comparable temperature dependence was observed for the solution of copolymer 3, whereby an increase in DCR was observed at 5°C. However, the solution of copolymer 6 indicated a much higher UCST at around 20°C (Figure ). Copolymer 6 has a similar DOT content to copolymers 3 and 4 but has a larger molar mass. These results indicate that the UCST behaviour of the copolymers under these conditions is influenced by both the presence of hydrophobic DOT moieties and the molar mass of the copolymer.