Poly(sulfur ylides): A new class of zwitterionic polymers with distinct thermal and solution behaviour

. The was degassed for and a for NMR analysis was taken ( t The was 70  C and the reaction was monitored by NMR. After the desired conversion was indicated, the reaction solution was allowed to reach to precipitated dropwise MeOH, re-dissolved 2 Cl 2 precipitated dropwise MeOH


Solubility
Solubility of poly(sulfur ylides) was determined by dissolving 10 mg of polymer in 3 ml of solvent (Table S1) at room temperature. The solution was stirred for one hour to guarantee full solubility. Solubility was determined by visual appearance.

Self-assemblies
Samples were prepared by dissolving PS-b-P(SY) 9 in DMF (8 mg/mL). The solution was diluted with water until the water content reached 33 v%. An aliquot (200 L) was rapidly diluted in water (5 mL) and filtered through syringe filters (0.22 M). The obtained samples were stored at room temperature.
Dynamic light scattering was conducted on block-copolymer PS-b-P(SY) 9 (0.24 mg/mL) using a Malvern DLS-Zetasizer. Samples for transmission electron microscopy (TEM) were prepared by air-drying of a solution of sample (5 µL) on a carbon-coated Cu TEM grid (200 mesh). JEOL TEM 1400 microscope with an acceleration voltage of 120 kV was utilized for analyzing the samples.
3. Organic acid: PS-co-P(SY) 5 was dissolved in TFA (2 ml) and it was incubated for 4 hours.  Figure S2 1 H-NMR of PS-co-P(SY) 5 in DMSO-d 6 A. After treatment with HCl, B. After treatment with TFA, C. After treatment with NaOH and D. Purified polymer prior incubation. The ratio of methyl signals to aromatic signals does not chance indicating that the polymer is not degrading under the given conditions.
Et 3 N (3.4 mL, 20.2 mmol) was added followed by T 3 P (5.3 mL, 8.73 mol). The mixture was stirred for a while and then (cyanomethyl)dimethylsulfonium bromide (1.48 g, 8.03 mmol) was added. The reaction mixture was stirred at room temperature overnight. It was then diluted with DCM and it was washed with sat. NaHCO 3 (x1), H 2 O (x1) and brine (x1). The crude product was dried over Na 2 SO 4 and purified via column chromatography on silica gel eluting with DCM/MeOH mixtures (gradient from 98:2 to 90:10 by volume) to obtain the product as brown solid (675 mg

General remarks
The obtained polymers were analyzed by 1 H-NMR and SEC. For determination of M n by NMR, the C-H signal adjacent to the RAFT agent was used (4.95-4.55 ppm, Figure S3). SEC analysis was done by using a polystyrene calibration. Please note that THF is not considered as a good solvent for poly(sulfur ylide); for that reason, the determined M n by SEC differs significantly for PS-co-P(SY), which display a high fraction of ylide. For PS-co-P(SY) with a minor fraction of ylide, M n determined by SEC is in good agreement with M n as determined by NMR. Figure S3.
Zoom-in of proton signal adjacent to dithioester, which was used for integration. analysis was taken (t = 0 h). The solution was heated to 80C -90C and the reaction was monitored by NMR. After the desired conversion was indicated, the reaction solution was S8 allowed to reach to room temperature and exposed to air. The product was precipitated dropwise in cold MeOH, re-dissolved in CH 2 Cl 2 and subsequently precipitated dropwise in cold MeOH again. The product was dried under vacuum overnight.

Differential scanning calorimetry
DSC trace of PS-co-P(SY) 7 with a heating rate of 10 K min -1 (T g = 180.0C). Please, note that above 210C, sulfur ylide bearing copolymers show signs of thermal degradation.  Figure S10.
Comparison of DSC trace of PS-co-P(SY) 5 after three cycles with a heating rate of 10 K min -1 . S12