Stefan Reinicke and Holger Schmalz* Makromolekulare Chemie II, Universität Bayreuth, D Bayreuth, Germany.

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1 Combination of living anionic polymerization and ATRP via click chemistry as a versatile route to multiple responsive triblock terpolymers and corresponding hydrogels Stefan Reinicke and Holger Schmalz* Makromolekulare Chemie II, Universität Bayreuth, D Bayreuth, Germany Holger.Schmalz@uni-bayreuth.de Tel.: +49 (0) , Fax: +49 (0) Supporting Information Synthesis of the azido acid chlorides, propargyl 2-bromoisobutyrate and ethyl 2-(4-acetylmethyl)triazolyl isobutyrate 2-Azidoisobutyryl chloride[1,2] 37 ml of ethyl 2-bromoisobutyrate (EBiB) and 31 ml ethanol were mixed in a one necked 250 ml flask equipped with a reflux condenser. After addition of 23 g NaN 3, dissolved in 60 ml H 2 O, the mixture was refluxed for 20 h at 98 C. Afterwards, the organic phase was separated and the remaining ethanol was removed using a rotary evaporator. The organic phase was then extracted twice with H 2 O and dried with CaCl 2. The first intermediate product, ethyl 2-azidoisobutyrate, was finally obtained by vacuum distillation (10 mbar, C). 18 ml of the ester were then mixed with 8.14 g KOH, dissolved in 28 ml H 2 O containing 10 vol% ethanol, and subsequently heated to C until the organic phase disappeared. After additional stirring for half an hour at C, the solution was poured over ice, acidified with conc. sulfuric acid, and extracted three times with diethyl ether. The combined organic fractions were washed with water and dried over Na 2 SO 4. The second intermediate product, 2-azidoisobutyric acid, was obtained by vacuum distillation (1.9 mbar, 70 C). In a last step, 9 ml of the acid were transferred to a flask equipped with a dropping funnel and a reflux condenser. The whole apparatus was held under nitrogen atmosphere. 7.5 ml of thionyl chloride were added dropwise to the preheated acid (50 C), and subsequently 1

2 the temperature was raised to 85 C. After the release of HCl had ceased, the mixture was refluxed for 1 h. Afterwards, the reflux condenser was removed and a distillation apparatus was attached to the flask. The final product was obtained by vacuum distillation. Azidoacetyl chloride[3] 46 g of bromo acetic acid were dissolved in 100 ml NaOH solution (3.3 M) under cooling. Subsequently, 25 g of NaN 3 and 10 ml of diethyl ether were added. The whole mixture was refluxed for approximately 60 h at 40 C. Afterwards, 175 ml of an ice/h 2 SO 4 (2 M) mixture were added and the solution was extracted three times with diethyl ether. The combined organic fractions were dried over Na 2 SO 4, and diethyl ether was removed using a rotary evaporator. The obtained crude product was transferred into the corresponding acid chloride according to the procedure described for the synthesis of 2-azidoisobutyryl chloride. Propargyl 2-bromoisobutyrate[4] 29 ml of propargyl alcohol were mixed with 69 ml triethylamine and 150 ml dichloromethane. After cooling down to 0 C, 115 g of 2-bromoisobutyryl bromide were added dropwise and the reaction mixture was stirred for 24 h at room temperature. Subsequently, the mixture was filtrated, washed with saturated sodium chloride solution, and dried over Na 2 SO 4. After the solvent was removed, the final product was obtained by vacuum distillation. Ethyl 2-(4-acetylmethyl)triazolyl isobutyrate 10 g propargyl acetate (Aldrich, 98%), 16 g ethyl 2-azidoisobutyrate (synthesized according to the procedure described above), 8 mg CuBr, and 50 ml THF were mixed in a reaction vessel equipped with a septum. After degassing by purging with N 2 for 30 min, 40 μl of degassed PMDETA were added. After one day, the mixture was passed through a basic alumina column, and the THF was removed using a rotary evaporator. The remaining product was used without further purification. 2

3 Cloud point measurements P(MEO 2 MA-co-MEO 8.5 MA)-2 was dissolved in Millipore water. PDMAEMA-1 was dissolved in ph = 8 and ph = 9 buffer (AVS Titrinorm), respectively. In each case, the concentration was fixed to 2.5 g/l. The cloud points were determined by turbidity measurements using a titrator (Titrando 809, Metrohm, Herisau, Switzerland) equipped with a turbidity probe (λ 0 = 523 nm, Metrohm) and a temperature sensor (Pt 1000, Metrohm). The temperature program (heating rate: 1 K/min) was run by a thermostat (LAUDA RE 306 and Wintherm_Plus software), using a homemade thermostatable vessel. The cloud points were determined from the intersection of the two tangents applied to the two linear regimes of the transmittance curves at the onset of turbidity. The cloud point of P(MEO 2 MA-co- MEO 8.5 MA)-2 is located at 32.8 C (Fig. S1a), whereas the cloud point of PDMAEMA-1 was found to be 53.8 C at ph = 8, and 42.4 C at ph = 9 (Fig. S1b), respectively. Fig. S1 Temperature-dependent transmittance (2.5 g/l, 1 K/min) for aqueous solutions of: a) P(MEO 2 MA-co- MEO 8.5 MA)-2, and b) PDMAEMA-1 at ph = 8 and ph = 9, respectively 3

4 ph-dependent dynamic light scattering (DLS) DLS was performed on an ALV DLS/SLS-SP 5022F compact goniometer system with an ALV 5000/E cross-correlator and a He-Ne laser (λ 0 = nm). The solutions (1g/L) were filtered with 0.8 μm syringe filters (Cameo) prior to the measurement. The decaline bath of the instrument was kept at 20 C using a LAUDA Proline RP 845 thermostat. The ph sweep was conducted using the DLS device in combination with a titrator (Titrando 809, Metrohm, Herisau, Switzerland). NaOH (titer 1M, Titrisol, Merck) was added in small portions of 2 μl, applying an equilibration time of 3 min after each titration step. All scattering data presented correspond to an average of five measurements, conducted for 1 min each. Figure S2 shows the distribution of apparent hydrodynamic radii of P2VP 56 -b-peo 370 -b-pdmaema 70 CSC micelles (P2VP core, PEO shell and PDMAEMA corona) at different ph. Two distributions are visible for each ph, indicating the presence of a major fraction of single CSC micelles (R h,app = nm) and some bigger micellar aggregates (R h,app 100 nm). The radius of the micelles decreases and the fraction of the bigger aggregates increases with decreasing ph (pk b (PDMAEMA) 7.7[5]). These findings point to intra- and intermicellar interactions between protonated DMAEMA and PEO chains most likely due to hydrogen bonding. Fig. S2 Intensity-weighted distribution of apparent hydrodynamic radii (R h,app ) of an aqueous solution of P2VP 56 - b-peo 370 -b-pdmaema 70 at different ph (1 g/l; θ = 90 ). The distributions of hydrodynamic radii were obtained using the CONTIN algorithm 4

5 References 1. Forster MO, Fierz HE (1908) LXI. The triazo-group. Part II. Azoimides of propionic ester and of methyl ethyl ketone. J Chem Soc, Trans 93: Huber WF (1955) Mono-α-aminoacyl and mono-α-dipeptide triglycerides. J Am Chem Soc 77: Wieland TH, Hennig HJ (1960) Aminosäure-Sulfimide. Chem Ber 93: Shi G-Y, Tang X-Z, Pan C-Y (2008) Tadpole-shaped amphiphilic copolymers prepared via RAFT polymerization and click reaction. J Polym Sci, Part A: Polym Chem 46: Plamper FA, Ruppel M, Schmalz A, Borisov O, Ballauff M, Müller AHE (2007) Tuning the thermoresponsive properties of weak polyelectrolytes: Aqueous solutions of starshaped and linear poly(n,n-dimethylaminoethyl methacrylate). Macromolecules 40: