Supporting Information
Self-Emulsion Polymerization of Baylis-Hillman Derived αHydroxymethyl Substituted Acrylates
Chao Peng, Abraham Joy
Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
Materials. 2-(Butylthiocarbonothioylthio)-2-methylpropanoic acid was synthesized according to
a reported procedure.1 4,4’-Azobis(4-cyanovaleric acid) and sodium bicarbonate were purchased
from Sigma-Aldrich. All other reagents were purchased from Alfa Aesar. Unless otherwise
stated, all reagents were used as received.
Analytical Methods. NMR spectra were recorded on a Varian NMRS 300 or 500 MHz
instrument. 1H NMR chemical shifts are reported in ppm relative to the solvent’s residual 1H
signal. 13C NMR spectra were recorded at 125 MHz. Size exclusion chromatography (SEC) in
THF was performed on a Waters 150-C Plus instrument equipped with RI and LS detectors and
PS was used as the standard. The glass transition temperature (Tg) of the polymers was
determined by differential scanning calorimetry (DSC) using TA Q2000 differential scanning
calorimetry instrument. The morphology of the nanoparticles was characterized by scanning
electron microscope (SEM) using JEOL-JSM-7401F with operating voltage as 4kV. The size of
the nanoparticles were determined by dynamic light scattering (DLS) using a Malvern
Instruments Zetasizer Nano ZS. The critical micelle concentrations (CMCs) of the monomers
were determined by surface tension method using a KSV NIMA KN 1003 Langmuir Trough and
by DLS method using a Brookhaven BI-200SM research goniometer and laser light scattering
system.
Monomer Synthesis
Scheme S1 Synthesis of alkyl α-hydroxymethyl acrylate (R = ethyl [1], n-butyl [2] or n-hexyl [3])
Synthesis of alkyl α-hydroxymethyl acrylate. As an example, the synthesis of n-butyl αhydroxymethyl acrylate (2) is as follows: n-butyl acrylate (4.23 g, 0.033 mol), formaldehyde
aqueous solution (3.75 mL, 0.05 mol), 1,4-diazabicyclo[2.2.2]octane (DABCO) (0.37 g, 0.0033
mol) and triethylamine (0.33 g, 0.46 mL, 0.0033 mol) were added to a round-bottom flask
equipped with a magnetic stir bar. THF (5.0 mL) and distilled water (3.2 mL) were added to the
flask. Then, the mixture was stirred at room temperature for 2 h followed by stirring at 55°C for
12 h. The compound was extracted by diethyl ether followed by washing with brine and
subsequent drying over anhydrous Na2SO4. The filtrate was then concentrated under reduced
pressure and purified by column chromatography (30% ethyl acetate and 70% hexane, Rf = 0.5)
to give a colorless liquid. (2.6 g, 50%)
1: 1H NMR (300 MHz, CDCl3) δ (ppm) 1.33 (t, J = 7.50 Hz, 3H), 2.23 (t, J = 6.00 Hz, 1H), 4.26
(q, J = 7.00 Hz, 2H), 4.35 (d, J = 3.00 Hz, 2H), 5.83 (s, 1H), 6.27 (s, 1H); 13C NMR (125 MHz,
CDCl3) δ (ppm) 14.09 (s), 60.80 (s), 62.36 (s), 125.37 (s), 139.59 (s), 166.29 (s).
2: 1H NMR (300 MHz, CDCl3) δ (ppm) 0.96 (t, J = 7.50 Hz, 3H), 1.36 – 1.49 (m, 2H), 1.64 –
1.73 (m, 2H), 2.25 (t, J = 6.00 Hz, 1H), 4.20 (t, J = 7.50 Hz, 2H), 4.35 (d, J = 3.00 Hz, 2H), 5.84
(s, 1H), 6.27 (s, 1H); 13C NMR (125 MHz, CDCl3) δ (ppm) 13.62 (s), 19.13 (s), 30.56 (s), 62.41
(s), 64.69 (s), 125.34 (s), 139.61 (s), 166.36 (s).
3: 1H NMR (300 MHz, CDCl3) δ (ppm) 0.90 (t, J = 7.50 Hz, 3H), 1.32 - 1.43 (m, 6H), 1.65 1.74 (m, 2H), 2.26 (s, 1H), 4.19 (t, J = 6.00 Hz, 2H), 4.34 (s, 2H), 5.84 (s, 1H), 6.27 (s, 1H); 13C
NMR (125 MHz, CDCl3) δ (ppm) 13.90 (s), 22.46 (s), 25.57 (s), 28.48 (s), 31.35 (s), 62.46 (s),
65.01 (s), 125.37 (s), 139.61 (s), 166.34 (s).
Figure S1 1H NMR spectrum of 1
Figure S2 1H NMR spectrum of 2
Figure S3 1H NMR spectrum of 3
Self-emulsion polymerization of α-hydroxymethyl acrylate under conventional radical
polymerization condition. In a typical experiment (P2), 2 (475 mg, 3 mmol), 4,4’-azobis(4cyanovaleric acid) (ABCVA) (0.84 mg, 0.003 mmol), NaHCO3 (0.87 mg, 0.01 mmol) and 3 mL
water were added to a round-bottom flask. The flask was degassed by bubbling nitrogen for 30
minutes. After that, the flask was sealed and sonicated for 30 seconds. Then, the flask was placed
in a heated oil bath at 70°C for 90 minutes under vigorous magnetic stirring. (Mn = 115.4 kg/mol,
PDI = 1.45)
P1. 1H NMR (300 MHz, Methanol-d4), δ (ppm): 1.31 (m, 3H), 2.00 (m, 2H), 3.83 (m, 2H), 4.10
(m, 2H).
P2. 1H NMR (300 MHz, CDCl3), δ (ppm): 0.97 (m, 3H), 1.42 (m, 2H), 1.64 (m, 2H), 1.92 (m,
2H), 3.59-4.07 (m, 4H).
P3. 1H NMR (300 MHz, Acetone-d6), δ (ppm): 0.96 (m, 3H), 1.40 (m, 6H), 1.71 (m, 2H), 2.00
(m, 2H), 3.73-4.07 (m, 4H).
Self-emulsion polymerization of α-hydroxymethyl acrylate under RAFT (reversible
addition-fragmentation chain transfer) polymerization condition. In a typical example (P2*),
2 (474 mg, 3 mmol), 4,4’-azobis(4-cyanovaleric acid) (ABCVA) (0.84 mg, 0.003 mmol),
NaHCO3 (0.87 mg, 0.01 mmol), 2-(butylthiocarbonothioylthio)-2-methylpropanoic acid (3.43
mg, 0.0136 mmol) and 3 mL water were added to a round-bottom flask. The flask was degassed
by bubbling nitrogen for 30 minutes. After that, the flask was sealed and sonicated for 30
seconds. Then, the flask was placed in a heated oil bath at 70°C for 180 minutes under vigorous
magnetic stirring. (Mn = 34.0 kg/mol, PDI = 1.24)
P2*. 1H NMR (500 MHz, CDCl3), δ (ppm): 0.97 (m, 3H), 1.42 (m, 2H), 1.64 (m, 2H), 1.92 (m,
2H), 3.59-4.07 (m, 4H).
P2-r-PBA. 1H NMR (500 MHz, CDCl3), δ (ppm): 0.96 (m, 6H), 1.39 (m, 4H), 1.62 (m, 4H),
1.80-2.20 (m, 4H), 2.29 (m, 1H), 3.40-4.40 (m, 6H).
Figure S4 1H NMR spectrum of P2
Figure S5 1H NMR spectra of the copolymers synthesized by self-emulsion RAFT
polymerization
Figure S6 SEC traces of the polymers synthesized by self-emulsion RAFT polymerization
Determination of critical micelle concentration (CMC)
Surface tension method. The measurements were carried out at 25 °C. The surface tension of a
series of surfactant solutions ranging from 0 to 10 mM was measured. The surface tension
(mN/m) was then plotted versus surfactant concentration (mM). The turning point in the curve
was determined as the critical micelle concentration (CMC).
Figure S7 CMC of 1 determined by surface tension method
Figure S8 CMC of 2 determined by surface tension method
Figure S9 CMC of 3 determined by surface tension method
DLS method. The measurements were carried out at 25 oC. The intensity of scattered light of a
series of surfactant solutions ranging from 0 to 60 mM was measured. The intensity (kcps) of
scattered light was then plotted versus surfactant concentration (mM). The turning point in the
curve was determined as the critical micelle concentration (CMC).
Figure S10 CMC of 1 determined by DLS method
Figure S11 CMC of 2 determined by DLS method
Figure S12 CMC of 3 determined by DLS method
SEM images of the latex produced by self-emulsion RAFT polymerization
Figure S13 SEM image of latex P2*
Figure S14 SEM image of latex P2(0.75)-r-PBA(0.25)
Figure S15 SEM image of latex P2(0.50)-r-PBA(0.50)
Figure S16 SEM image of latex P2(0.25)-r-PBA(0.75)
References
1. N. Haridharan, K. Ponnusamy, R. Dhamodharan. J. Polym. Sci., Part A:
Polym. Chem. 2010, 48, 5329-5338.