SUPPORTING INFORMATION Polymerization-induced Self-Assembly of Homopolymer and Diblock copolymer: A Facile Approach for preparing Polymer Nano-objects with Higher Order Morphologies Jianbo Tan *a,b, Chundong Huang a, Dongdong Liu a, Xueliang Li a, Jun He a, Qin Xu a, Li Zhang *a,b a Department of Polymeric Materials and Engineering, School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China b Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, Guangzhou 510006, China *Corresponding authors: tanjianbo@gdut.edu.cn, lizhang@gdut.edu.cn 1
EXPERIMENTAL SECTION Materials. Styrene (St, Aladdin) was purified by passing through a basic alumina oxide (Aladdin) column prior to storage at 4 o C. Monomethoxy poly(ethylene glycol) (mpeg45, 2000 g/mol, Energy Chemical), dicyclohexylcarbodiimide (DCC, Aladdin), 4-dimethylaminopyridine (DMAP, Aladdin), sodium 4,4-dimethyl-4-silapentane-1-sulfonate (DSS), and hydroquinone (Aladdin) were used without further purification. 2, 2-Azobisisobutyronitrile (AIBN, Aladdin) was recrystallized from ethanol prior to storage under refrigeration at 4 C. S-1-dodecyl-S -(α,α -dimethyl-α -acetic acid) trithiocarbonate (DDMAT) and S,S -bis(α,α -dimethyl-α -acetic acid) trithiocarbonate (BDMAT) were synthesized according to a published procedure. 1 Characterization. The polymerization reaction mixtures were diluted 100-fold with methanol-water mixtures. A drop of the solution was placed on the copper grip for 1 min and then blotted with filter paper to remove excess solution. Transmission electron microscope (TEM) observations were carried out on a FEI Tecnai G2 Spirit instrument operated at 120 kv. TEM images at different tilting angels were recorded with a FEI Tecnai G2 F30 microscope operated at 300 kv. Data were acquired using FEI's automated tomography software with a tilt series of -60 to +60 degrees. Scanning electron microcopy (SEM) images were collected using a Hitachi S4800 electron microscope on samples sputter-coated with gold prior imaging. The sample for SEM imaging was 2
prepared by drop casting the diluted dispersion on mica films and drying at ambient temperature prior to sputter-coating. The molecular weight and polydispersity of the block copolymers were measured by gel permeation chromatography (GPC) at 35 o C using a Waters 1515 GPC instrument with tetrahydrofuran (THF) as the mobile phase and Waters styragel HR1, HR4 columns. The flow rate of THF was 1.0 ml/min. Linear polystyrene polymers with narrow molecular weight distributions were used as the standards to calibrate the apparatus. 1 H NMR spectra were recorded in CDCl3 using a Bruker Avance III 400 MHz NMR spectrometer at a temperature of 25 o C. Note: The samples prepared by PISA were first diluted with methanol, and then dissolved in CDCl3. Synthesis of mpeg45-ddmat. A solution of DDMAT (7.29 g, 20 mmol) in 40 ml of anhydrous dichloromethane (DCM) was introduced in a dry flask under nitrogen atmosphere containing mpeg45 (20 g, 10 mmol). Then a solution of DCC (4.12 g, 20 mmol) and DMAP (0.244 g, 2 mmol) in 10 ml of anhydrous THF was added dropwise to the reaction mixture at 0 C. The esterification reaction proceeded under stirring at room temperature for 48 h. The polymer was collected by precipitation of the reaction mixture in hexane, and finally dried at 45 o C under vacuum to obtain a yellow powder. THF GPC confirmed Mn = 3600 g/mol, Mw/Mn = 1.05. RAFT dispersion polymerization using a mixture of DDMAT and mpeg45-ddmat. In a typical experiment ([DDMAT]/[mPEG45-DDMAT] = 1/1, target DP = 200, [St] = 15% w/w): 3
Styrene (1.5 g, 14.4 mmol), mpeg45-ddmat (0.085 g, 0.036 mmol), DDMAT (0.013g, 0.036 mmol), AIBN (0.0039 g, 0.024 mmol), and methanol/water (6.8 g/1.7 g, 80/20, w/w) were weighed into a 25 ml round bottom flask to form a homogenous solution. The reaction mixture was purged with nitrogen for 20 min, sealed, and immersed into a 70 o C pre-heated oil bath. The reaction was conducted for 24 h under magnetic stirring and quenched by immersing into an ice-water bath. Kinetic study of RAFT dispersion polymerization ([DDMAT]/[mPEG45-DDMAT] = 1/1). Styrene (2.5 g, 24 mmol), mpeg45-ddmat (0.142 g, 0.06 mmol), DDMAT (0.022g, 0.06 mmol), AIBN (0.0066 g, 0.04 mmol), and methanol/water (11.33 g/2.83 g, 80/20, w/w) were weighed into a 25 ml round bottom flask to form a homogenous solution. The reaction mixture was purged with nitrogen for 20 min, sealed, and immersed into a 70 o C pre-heated oil bath. Samples were extracted using syringes under nitrogen at different times. The obtained samples were characterized by 1 H NMR and THF gel permeation chromatography (GPC). RAFT dispersion polymerization using a mixture of BDMAT and mpeg45-ddmat. In a typical experiment ([BDMAT]/[mPEG45-DDMAT] = 1/1, target DP = 200, [St] = 15% w/w): Styrene (1.5 g, 14.4 mmol), mpeg45-ddmat (0.057 g, 0.024 mmol), BDMAT (0.0068g, 0.024 mmol), AIBN (0.0039 g, 0.024 mmol), and methanol/water (6.8 g/1.7 g, 80/20, w/w) were weighed into a 25 ml round bottom flask to form a homogenous solution. The reaction mixture was purged with nitrogen for 20 min, sealed, and immersed into a 70 o C pre-heated oil bath. The 4
reaction was conducted for 24 h under magnetic stirring and quenched by immersing into an ice-water bath. 5
ADDITIONAL RESULTS -DDMAT/[DDMAT] = 1/0 -DDMAT/[DDMAT] = 4/1 -DDMAT/[DDMAT] = 3/1 -DDMAT/[DDMAT] = 2/1 -DDMAT/[DDMAT] = 1/1 16 18 20 22 24 Elution volume (ml) Figure S1. GPC profiles of RAFT dispersion polymerization of styrene (target DP = 200) with different [mpeg45-ddmat]/[ddmat] ratios at a 15% w/w styrene concentration in a methanol-water mixture (80/20, w/w). Table S1. GPC data of RAFT dispersion polymerization of styrene (target DP = 200) with different [mpeg45-ddmat]/[ddmat] ratios at a 15% w/w styrene concentration in a methanol-water mixture (80/20, w/w). 6
Figure S2. SEM image of polymer nano-objects prepared via PISA of St (15% w/w St concentration) in methanol-water (80/20, w/w) with a [DDMAT]/[mPEG-DDMAT] ratio of 1.0 (target DP of 200). Figure S3. TEM images of samples extracted during the kinetic study. 7
PSt n -PSt n homopolymer -DDMAT]/[BDMAT] = 8/1 -DDMAT]/[BDMAT] = 6/1 -DDMAT]/[BDMAT] = 4/1 -DDMAT]/[BDMAT] = 2/1 -DDMAT]/[BDMAT] = 1/1 mpeg 45 -PSt n block copolymer 16 17 18 19 20 21 22 Elution volume (ml) Figure S4. GPC profiles of RAFT dispersion polymerization of styrene (target DP = 200) with different [mpeg45-ddmat]/[bdmat] ratios at a 15% w/w styrene concentration in a methanol-water mixture (80/20, w/w). Table S2. GPC data of RAFT dispersion polymerization of styrene (target DP = 200) with different [mpeg45-ddmat]/[bdmat] ratios at a 15% w/w styrene concentration in a methanol-water mixture (80/20, w/w). 8
Figure S5. TEM images of polymer nano-objects prepared by RAFT dispersion polymerization of styrene (target DP = 200) with different [BDMAT]/[mPEG45-DDMAT] ratios at a 15% w/w styrene concentration in a methanol-water mixture (80/20, w/w). Figure S6.TEM images of polymer nano-objects prepared by RAFT dispersion polymerization of styrene (target DP = 200) with [mpeg45-ddmat]/[bdmat] = 1/0 at different styrene concentrations in a methanol-water mixture (80/20, w/w). 9
Figure S7. (a) TEM image of mpeg45-pst192 vesicles prepared via RAFT dispersion polymerization at 15% w/w styrene in a methanol/water mixture (80/20, w/w), (b) TEM image of the sample (a) swelled with styrene ([mpeg45-pst192]/[st] = 200/1) in a methanol-water mixture (60/40, w/w) at 70 o C for 30 min, (c) TEM image of the sample (a) swelled with toluene in a methanol-water mixture (60/40, w/w) at 70 o C for 30 min. Figure S8. TEM images of the sample of PSt184/mPEG45-PSt184 (1/1) vesicles prepared by RAFT dispersion polymerization of styrene (15% w/w) at different tilting angels: (a) -60 degree, (b) 0 degree, (c) 60 degree. REFERENCE (1) Lai, J. T.; Filla, D.; Shea, R. Macromolecules 2002, 35 (18), 6754. 10