RAFT Polymerization of Methacrylic Acid in Water - American

Article pubs.acs.org/Macromolecules

RAFT Polymerization of Methacrylic Acid in Water Isabelle Chaduc, Muriel Lansalot,* Franck D’Agosto,* and Bernadette Charleux Laboratoire de Chimie Catalyse Polymères et Procédés (C2P2), Université de Lyon 1, CPE Lyon, CNRS UMR 5265, Equipe LCPP Bat 308F, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France S Supporting Information *

ABSTRACT: Reversible addition−fragmentation chain transfer (RAFT) polymerization of methacrylic acid was successfully performed in water in the presence of a trithiocarbonate, the 4-cyano-4-thiothiopropylsulfanylpentanoic acid (CTPPA), as a RAFT agent. Several parameters such as the temperature, the concentration, the pH, the targeted polymerization degree, and the initiator concentration were studied. For pH value below the pKa of MAA, well-defined PMAA chains with different molar mass up to 92 000 g mol−1 exhibiting low dispersity (Đ < 1.19) were obtained under a broad range of synthetic conditions.

■

nitroxide started to degrade under the conditions employed.18 Because of the interaction of the carboxylic acid moiety of MAA with the metallic catalyst, atom transfer radical polymerization (ATRP) failed19,20 to control the polymerization of MAA. Armes et al.21 circumvented this limitation by polymerizing sodium methacrylate in water. Reversible addition−fragmentation chain transfer (RAFT)22 is probably the most monomercompatible CRP technique and has been extensively used to control the polymerization of water-soluble monomers.5 Surprisingly, only a limited number of papers are dealing with RAFT of MAA, which was successfully conducted in the presence of a dithiobenzoate control agent in DMF,6 in methanol,7,9 in dioxane,8 and in mixtures of dioxane and water (1:4 v/v).9 Despite the aqueous properties of MAA and PMAA and as far as we know, the use of water as a solvent for the CRP of MAA has, however, not been investigated. We recently showed that amphiphilic block copolymers could be synthesized in water using a one-pot strategy23 starting with the successful RAFT synthesis of the hydrophilic segment including PMAA segmentin water. While the emphasis was put on the block copolymer synthesis in that previous work, the present paper reports the first detailed study of the RAFT polymerization of MAA in water. Reactions were carried out in presence of 4-cyano-4-thiothiopropylsulfanylpentanoic acid

INTRODUCTION Water-soluble homopolymers and copolymers are of high technical importance for many applications. Poly(methacrylic acid) (PMAA) is a polyelectrolyte with aqueous solution properties that can be tuned with the pH or the ionic strength. Synthesized by free radical polymerization of a monomer commonly used in the industry, methacrylic acid (MAA), PMAA finds applications in a broad range of areas such as the coating industry1 or drug delivery systems.2,3 PMAA is also particularly interesting when introduced into more complex macromolecular architectures such as amphiphilic block copolymers. The corresponding syntheses require the use of controlled polymerization techniques. Direct controlled polymerization of MAA can only be achieved by the use of a free radical process. However, despite the fantastic advances made in the area of controlled radical polymerization (CRP),4,5 only a limited number of papers report the direct CRP of MAA.6−9 Among the different available CRP techniques, nitroxidemediated polymerization (NMP)10,11 is not particularly well suited for methacrylate derivatives. Indeed, the polymerization of methacrylates can only be controlled with the use of a specific nitroxide12 or if a small amount of styrenic13,14 or acrylonitrile15 comonomer is employed. This has indeed been valuably applied to the polymerization of MAA in organic solution.16,17 Very recently, we showed that MAA could be polymerized under controlled conditions in acidic water in the presence of a small fraction of styrenesulfonate as long as the polymerization time remained short enough, after which SG1 © 2012 American Chemical Society

Received: October 25, 2011 Revised: January 6, 2012 Published: January 26, 2012 1241

dx.doi.org/10.1021/ma2023815 | Macromolecules 2012, 45, 1241−1247

Macromolecules

Article

Table 1. Experimental Conditions and Results for the RAFT Polymerization of MAA with [MAA]/[CTPPA] = 43a entry

[MAA]0 (mol L−1)

solvent

T (°C)

1 2 3 4 5 6 7 8 9 10b 11b 12b 13c

4.6 4.6 4.6 1 1 1 5.8 2.8 2.5 2.5 2.5 2.5 2.5

methanol water dioxane water dioxane water water water water water water water water

70 70 70 80 80 70 70 70 80 80 80 80 80

pH

time (h)

conv (%)

Mn(theo) (g mol−1)

Mn(exp) (g mol−1)

Mw/Mn

7 5.5 6 4 6.5 7 4 5 4 4 7 6 6

59 100 91 98 47 98 100 99 100 99 96 71 88

3050 4000 3680 3930 2010 3930 4000 3950 4000 3960 3515 3600 3560

3330 4665 3940 4020 2580 4300 4760 4510 4440 4340 3850 2925 3192

1.27 1.16 1.20 1.15 1.24 1.11 1.19 1.17 1.15 1.12 1.47 2.59 2.78

2.1 2.3 2.3 2.0 2.2 2.2 4 5 7 6.8

a

MAA RAFT polymerizations were performed using ACPA as initiator and CTPPA as chain transfer agent [CTPPA]/[ACPA] = 10. bpH was adjusted by NaOH addition. cThis experiment was performed with methacrylate sodium.

Scheme 1. Synthesis of Poly(methacrylic acid) by RAFT Polymerization

RAFT Polymerizations in Water. An example of RAFT polymerization of MAA is as follows (entry 4 in Table 1). In a twonecked round-bottom flask equipped with a condenser 149 mg of CTPPA (2.29 × 10−2 mol L−1) and 15 mg of ACPA (2.29 × 10−3 mol L−1) were dissolved in 2 g of MAA (0.99 mol L−1) and 4 mL of water. 349 mg of 1,3,5-trioxane (1.65 × 10−1 mol L−1) was added as an internal reference for NMR analysis. 19.5 mL of water was finally added. After deoxygenation by nitrogen bubbling for 30 min, the resulting mixture was immersed in an oil bath thermostated at 80 °C. The regular withdrawal of samples allowed us to follow the monomer conversion as a function of time and the evolution of molar masses and molar mass distributions as a function of monomer conversion. The monomer conversion was determined by 1H NMR spectroscopy in D2O by the relative integration of the protons of 1,3,5-trioxane and the vinylic protons of MAA. Theoretical molar masses were obtained using the following equation:

(CTPPA) trithiocarbonate used as chain transfer agent (CTA) and 4,4′-azobis(4-cyanopentanoic acid) (ACPA) as watersoluble initiator. Different parameters such as the temperature, the MAA concentration, the pH, the targeted polymerization degree, and the ACPA content were studied. We show that well-defined PMAA chains can be obtained under a broad range of conditions and can exhibit narrowly distributed molar masses (dispersity (Đ) < 1.10) up to 92 000 g mol−1.

■

EXPERIMENTAL SECTION

Materials. Methacrylic acid (MAA, Acros, 99.5%), sodium methacrylate (Aldrich, 99%), 4,4′-azobis(4-cyanopentanoic acid) (ACPA, Fluka, >98%), 1,4-dioxane (Sigma-Aldrich, 99.5%), and methanol (Laurylab, 99%) were used as received. Water was deionized before use (Purelab Classic UV, Elga LabWater). 4-Cyano-4thiothiopropylsulfanylpentanoic acid (CTPPA) was obtained by reaction of ACPA with bis(propylsulfanylthiocarbonyl) disulfide as described in the literature.24,25 Analytical Techniques. MAA conversion was determined by 1H NMR spectroscopy in D2O or DMSO (when the solvent is dioxane) at room temperature (Bruker DRX 300). Size exclusion chromatography (SEC) measurements were performed in THF at 40 °C, at a flow rate of 1 mL min−1, using toluene as a flow rate marker. Before analysis, the polymers were modified by methylation of the carboxylic acid groups using trimethylsilyldiazomethane. 26 They were analyzed at a concentration of 3 mg mL−1 after filtration through a 0.45 μm poresize membrane. The separation was carried out on three Polymer Laboratories columns [3 × PLgel 5 μm Mixed C (300 × 7.5 mm) and a guard column (PL gel 5 μm)]. The setup (Viscotek TDA 305) was equipped with a refractive index (RI) detector (λ = 930 nm). The average molar masses (number-average molar mass Mn and weightaverage molar mass Mw) and the dispersity value (Đ = Mw/Mn) were derived from the RI signal by a calibration curve based on poly(methyl methacrylate) standards (PMMA from Polymer Laboratories).

Mn =

MMAA [MAA]0 x + MCTPPA [CTPPA]0

where Mn is the number-average molar mass, MMAA and MCTPPA are the molar masses of MAA and CTPPA, respectively, [MAA]0 and [CTPPA]0 are the initial concentrations of CTPPA and MAA, respectively, and x is the fractional conversion of MAA.

■

RESULTS AND DISCUSSION In their original study, Pelet et al.9 nicely polymerized MAA in methanol using 4-cyanopentanoic acid dithiobenzoate (CPADB) as RAFT agent. They investigated the potential use of a water-based solvent and performed the same polymerization in a mixture of dioxane and water (1:4, v/v). Dioxane was indeed required as a cosolvent since CPA-DB was insoluble in pure water. However, under these conditions, a remarkable increase in viscosity was observed after 90% conversion, accompanied by a deviation of the molar masses from the theoretical Mn and 1242


Macromolecules

Article

Figure 1. RAFT polymerization of MAA performed in different solvents and at different temperatures. [MAA]/[CTPPA] = 43, [CTPPA]/[ACPA] = 10, [MAA] = 4.5 mol L−1 at T = 70 °C, and [MAA] = 1 mol L−1 at T = 80 °C. Evolution of (a) monomer conversion versus time and (b) numberaverage molar mass Mn (full symbols) and Đ = Mw/Mn (open symbols) versus conversion. Straight line is the theoretical evolution of molar masses with conversion.

Figure 2. RAFT polymerization of MAA performed in water and at different temperatures. [MAA] = 1 mol L−1, [MAA]/[CTPPA] = 43, [CTPPA]/ [ACPA] = 10. Evolution of (a) monomer conversion versus time and (b) number-average molar mass Mn (full symbols) and Đ = Mw/Mn (open symbols) versus conversion. Straight line is the theoretical evolution of molar masses with conversion.

with a change of color of the medium. The potential hydrolysis of the dithiobenzoate based CTA was put forward. The authors mentioned that the selection of chain transfer agents of higher solubility such as trithiocarbonates could prevent this issue. In addition, trithiocarbonate are known to be less subjected to hydrolysis.27,28 We then selected CTPPA to perform our experiments in pure water (Scheme 1). It is worth mentioning here that CTPPA is not highly soluble in water. In all our experiments, CTPPA, ACPA, MAA, and a small amount of water were first mixed, and the resulting mixture was then added to the remaining of water. The starting polymerization medium was not homogeneous and exhibited small droplets of an organic phase suspended in water, particularly at low concentration of MAA. The rough suspension was turned into a very homogeneous but still slightly turbid solution upon heating, which quickly cleared up. Effect of the Polymerization Solvent. The first series of experiments aimed at comparing the value that the use of water would add in terms of control compared to the solvents that were already used in the literature (Table 1, entries 1−3). RAFT polymerizations of MAA were thus performed at 70 °C with a concentration of MAA of 4.6 mol L−1. An experiment carried out in water (entry 2) was compared to experiments performed in methanol (entry 1) and dioxane (entry 3) under the same conditions. In all the cases, an inhibition period was observed (Figure 1a). When methanol and dioxane were used as solvent, conversion of 59 and 91% were reached in 7 and 6 h, respectively. Quantitative conversion was reached in less than 5 h in water. Whatever the solvent, a linear increase of molar mass was observed with increasing conversion showing the

controlled features of the studied systems, although molar masses were slightly higher than theoretical values particularly for low conversions (Figure 1b). The dispersity Đ attained was, however, much lower in water (1.16) than in methanol or dioxane (1.30). [MAA]0 used in these experiments remained high and did not really show the advantage of using water as solvent. An experiment was then performed at much lower concentration of MAA in water (1 mol L−1, Table 1, entry 4) and compared to the same experiment carried out in dioxane (entry 5). In order to keep reasonable polymerization time, the temperature was increased to 80 °C. Again, well-defined PMAA chains were formed in both cases with, however, better control features in the case of water (Table 1). In addition, the use of water as solvent allowed to reach higher conversion with a higher polymerization rate (98% in 4 h) than in dioxane (47% in 6.5 h). As can be deduced from these first experiments, while the choice of the solvent does not dramatically impact the quality of the control, it has a great effect on the polymerization kinetics. Indeed, the propagation rate coefficient, kp, in freeradical polymerization of MAA is dependent on the solvent. Kuchta et al.29 studied the effect of water and organic solvents such as DMSO and methanol on the propagation rate in MAA polymerization via pulsed-laser polymerization. They showed that kp values obtained in water were higher than those obtained in DMSO or methanol, due mainly to a lower activation energy. This was explained by a higher tendency of the monomers to be self-associated in organic solvents via 1243


Macromolecules

Article

Figure 3. RAFT polymerization of MAA performed at different concentrations of MAA in water at 70 °C. [MAA]/[CTPPA] = 43 and [CTPPA]/ [ACPA] = 10. Evolution of monomer conversion versus time and corresponding ln(1/(1 − x)) = f(t) plots where x is MAA conversion.

Figure 4. RAFT polymerization of MAA performed in water at 80 °C at different pH. [MAA] = 2.5 mol L−1, [MAA]/[CTPPA] = 43, and [CTPPA]/[ACPA] = 10. Evolution of (a) monomer conversion versus time, (b) number-average molar mass Mn (full symbols) and Đ = Mw/Mn (open symbols) versus conversion. Straight line is theoretical evolution of molar masses with conversion. Corresponding SEC chromatogram evolutions for (c) pH = 2.2 and (d) pH = 5.

was reached in 4 h whereas 7 h was necessary to reach the same conversion at 70 °C (Figure 2a). Nevertheless, the control features were exactly the same and well-defined PMAA chains were obtained with narrowly distributed (Đ < 1.15) molar masses that increased linearly with conversion. As observed previously, final molar masses were nicely matching the theoretical values (Figure 2b) although being slightly higher than expected at low conversions. Effect of the MAA Concentration. MAA concentrations were varied from 1 up to 5.8 mol L−1 (entries 6, 8, 2, and 7 in Table 1). As observed by Pelet et al.,9 the polymerization became faster when the MAA concentration was increased. Quantitative conversions were obtained in all the cases. Slightly higher dispersities were observed (Đ between 1.16 and 1.19) when the [MAA] concentrations were increased (Figure 3) compared to the polymerization performed at 1 mol L−1 (1.11). The final molar mass values were also higher in those cases (4760 g mol−1) than the ones obtained for [MAA] of 1 mol L−1

hydrogen bondings, hence leading to the need for a higher energy to break these bonds for the propagation step. Eventually, contrary to what Pelet et al.9 observed when using dioxane/water mixture as solvent the use of pure water did not lead to the discoloration of the medium. The choice of our CTPPA trithiocarbonate and our polymerization procedure seemed thus to be a good combination to control the polymerization of MAA in pure water. To further investigate the potential of this interesting system, the influence of various parameters such as the temperature, the MAA concentration, the pH, the targeted molar mass, and the initiator content were studied. Effect of Temperature. The effect of the temperature was further studied by performing two experiments at 70 and 80 °C under exactly the same conditions ([MAA] = 1 mol L−1, entries 6 and 4, respectively, in Table 1). After a short inhibition period of about 30 min, a faster polymerization was observed when performing the reaction at 80 °C, for which 98% conversion 1244


Macromolecules

Article

Table 2. Influence of the Monomer/RAFT Agent Ratio in the RAFT Polymerization of MAAa

a

entry

[MAA]0/[CTPPA]0

[CTPPA]0/[ACPA]0

time (h)

conv (%)

Mn(theo) (g mol−1)

Mn(exp) (g mol−1)

Mw/Mn

4 14 15 16 17 18

43 287 578 1158 1158 1158

10 10 10 10 5 2.5

4 8 8 8 8 5

98 96 94 77 100 96

3 930 24 040 47220 76 620 100 000 99 000

4 020 24 880 42 830 74 410 92 210 82 370

1.15 1.07 1.08 1.11 1.10 1.15

MAA RAFT polymerizations were performed in water at 80 °C using ACPA as initiator and CTPPA as chain transfer agent. [MAA] = 1 mol L−1.

Figure 5. RAFT polymerization of MAA performed in water at 80 °C at different [MAA]/[CTPPA] ratios. [MAA] = 2.5 mol L−1 and [CTPPA]/ [ACPA] = 10. (a) Evolution of number-average molar mass Mn versus conversion. Straight line is theoretical evolution of molar masses with conversion and (b) SEC chromatogram evolution for [MAA]/[CTPPA] = 1158.

(3930 g mol−1) and higher than the expected ones (around 4000 g mol−1). The increase in viscosity observed at the end of the polymerization in the experiments carried out at high concentrations of MAA may cause these variations to the theory. Lacik et al.30,31 performed careful studies on the propagation kinetics of free radical polymerization of MAA in aqueous solution. Using data obtained from the pulsed laser polymerization−size exclusion chromatography (PLP-SEC) technique, the authors showed that kp may be divided by ∼4 by increasing MAA concentration from 8 to 49 wt % (range of concentrations used in the present study). Figure 3 seems however to be in contradiction with these results. The same molar masses were targeted here (ca. 4000 g mol−1), and a constant molar ratio CTPPA/ACPA of 10 was employed. Thus, the concentration of initiator constantly increased when [MAA] was increased. Indeed, [ACPA] was 5.8 times higher in experiment 7 than in experiment 6. This may overcompensate the decrease of kp suggested by Lacik et al.30,31 and result in the observed increase of polymerization rate with MAA concentrations. Nevertheless, the control of the polymerization remained very good for the broad range of concentrations employed, showing the versatility of this robust polymerization system. Effect of pH. As polymerizations were performed in water to produce PMAA that is a polyelectrolyte, the pH may impact the control of the polymerization. In order to assess the effect of this parameter, four experiments were carried out at pH 2.2, 4, 5, and 7 (entries 9−12, Table 1). As shown in Table 1 and in Figure 4, the ionization of MAA has a drastic impact on both the kinetics and the control of the polymerization. The higher the pH was, the slower the polymerization (Figure 4a). Like the effect of MAA concentration on kinetics, this result was already observed by Lacik et al.,30,31 who reported a decrease of 1 order of magnitude for kp from nonionized to fully ionized MAA.

This apparently entropic effect (not temperature dependent) was related to a variation of the pre-exponential factor in the Arrhenius expression. This factor is impacted by intermolecular interactions giving rise to a hindrance of internal rotational mobility of the transition state structure, affecting the propagation step. This hindrance can be induced by both intermolecular hydrogen-bonded interactions (in nonionized MAA) and electrostatic interactions32,33 of partially or fully ionized MAA carboxylic acid groups in the MAA moieties. Experiments carried out at pH = 2.2 or 4 reached quantitative conversion and exhibited a good control of the polymerization as shown by the low dispersity values obtained (1.15 and 1.12, respectively, entries 9 and 10 in Table 1) and by the linear increase of molar masses with conversion (Figure 4b and corresponding SEC chromatograms in Figure 4c). It is interesting to note that, in addition, the control of the polymerization seemed to be strongly affected for pH higher than the pKa of MAA (pKaMAA = 4.3634). In this case (pH = 5, Table 1) dispersity values started to increase (Đ = 1.47, entry 11) and molar mass values escaped the linear expected evolution with conversion (pH = 5 in Figure 4b and corresponding SEC chromatograms in Figure 4d). The experiment carried out at pH 7 was not controlled anymore (Đ = 2.59, entry 12). These systems containing partially or fully ionized MAA together with partially ionized PMAA species may be rather complex due to the simultaneous occurrence of electrostatic interactions, the effects of ionic strength, the impact of electrochemical equilibria, and the action of hydrophobic forces.30,31 In order to simplify the variety of origins of these phenomena, an additional experiment was performed with sodium methacrylate as monomer (13, Table 1) using the same conditions as the ones of the last series. As expected, the polymerization was slow compared to polymerization performed under acidic conditions. However, no control of the 1245


Macromolecules

Article

Figure 6. RAFT polymerization of MAA performed in water at 80 °C for different [CTPPA]/[ACPA] ratios. [MAA] = 1 mol L−1 and [MAA]/ [CTPPA] = 1158. Evolution of (a) monomer conversion versus time, (b) number-average molar mass Mn (full symbols) and Đ = Mw/Mn (open symbols) versus conversion. Straight line is theoretical evolution of molar masses with conversion.

faster with 96% conversion reached in 8 h for experiment 17 and quantitative conversion in the case of 18 in 5 h. Besides, Figure 6b showed that a good control of the growth of the chains was maintained all over the course of the polymerization and that PMAA chains of 92 210 g mol−1 (Đ = 1.10) could be produced.

polymerization was observed. Explaining the origin of the loss of control would then be risky with the experimental data obtained in this paper. The RAFT agent is less sensitive to hydrolysis in reactions performed at a low pH. However, the aforementioned hindrance effect induced by electrostatic interactions of partially or fully ionized MAA carboxylic acid groups in the MAA moieties that impact kp may also impact in the same way the addition−fragmentation steps and thus the RAFT control. Besides, the sharp change in PMAA conformation from hypercoil to rod known to occur around pH 535 may also impact the reversible chain transfer kinetics. Synthesis of Well-Defined High Molar Mass PMAA. The powerful RAFT polymerization system of MAA in water presented in this paper seemed to be an interesting way to produce well-defined PMAA chains under a broad range of conditions. In addition, the use of water as solvent strongly decreases the probability of transfer reactions that are often encountered in organic solvents. Compared to acrylic acid, the polymerization of methacrylic acid has the advantage of not involving 1,5-hydrogen shift reactions36 that give rise to branched structures and sometimes impede the formation of high molar mass chains. Experiments were then carried out in order to target high molar mass PMAA (Table 2) by varying either [MAA]/[CTPPA] or [ACPA]. As shown in Figure 5a, whatever the final molar mass targeted, linear evolutions of experimental molar mass values versus conversion were observed in all the cases and dispersities remained lower than 1.15 (see Figure 5b and Figure S2 for SEC chromatograms corresponding to [MAA]/CTPPA] = 43, 287, and 578). An excellent agreement between experimental and theoretical molar masses was obtained (Table 2), underlining the fact that the deviations observed in previous experiments (Mn,targeted = 4000 g mol−1) particularly at low conversions were probably due to a rather low chain transfer ability of CTPPA in MAA polymerization. The time for the RAFT equilibrium to take place (up to 20% conversion),22 the length of the inhibition period increased with [MAA]/CTPPA] ratio (30 min for [MAA]/CTPPA] = 43, 90 min for the highest [MAA]/ CTPPA] = 1158; see Figure S1 in the Supporting Information), and the molar mass values were slightly higher than expected. These molar masses were then quickly reaching the expected values. Well-defined PMAA chains exhibiting molar masses up to 74 410 g mol−1 (Figure 5b) were obtained with dispersity as low as 1.11 (see also Figure S2). However, reaction times were in the range of 8 h. To shorten the polymerization, experiments 17 and 18 were performed under the same conditions as experiment 16 with increasing [ACPA]. As expected (Figure 6a), polymerizations were much

■

CONCLUSION RAFT polymerization of methacrylic acid (MAA) was performed in water in the presence of a trithiocarbonate as chain transfer agent (4-thiothiopropylsulfanylpentanoic acid, CTPPA) and 4,4′-azobis(4-cyanopentanoic acid) (ACPA) as initiator. A particular feature of this system is that CTPPA is first dissolved in MAA and then added to water. The resulting mixture is a suspension of organic droplets in water that is turned into a slightly turbid solution upon heating, which quickly cleared up. A first comparison of different experiments performed in water, in methanol, and in dioxane showed the far superiority of this aqueous polymerization system in terms of both kinetics and control of the molar masses. Then various parameters such as the temperature of the polymerization, the MAA concentration, and the pH were further studied. Over a broad range of conditions, the system obeyed to a controlled polymerization system, and well-defined PMAA chains exhibiting dispersities lower than 1.19 were obtained. However, when increasing the pH, the control features were rapidly lost above the pKa of MAA. Eventually, the system proved to be an excellent tool to produce high molar mass PMAA (>90 000 g mol−1) achieving very low dispersity (Đ = 1.10).

■

ASSOCIATED CONTENT

S Supporting Information *

Conversions versus time during RAFT polymerization of MAA performed in water at 80 °C at different [MAA]/[CTPPA] ratios; SEC chromatogram evolutions for RAFT polymerizations of MAA performed in water at 80 °C at different [MAA]/[CTPPA] ratios. This material is available free of charge via the Internet at http://pubs.acs.org.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected] (M.L.); [email protected] (F.D.).

■

ACKNOWLEDGMENTS The financial support from the French National Agency for Research (ANR ALGIMAT 09-CP2D-02) and the competitive1246


Macromolecules

Article

(33) Tanaka, H.; Araki, T. Phys. Rev. Lett. 2000, 85, 1338. (34) Katchalsky, A.; Blauer, G. Trans. Faraday Soc. 1951, 47, 1360− 1370. (35) Ruiz-Perez, L.; Pryke, A.; Sommer, M.; Battaglia, G.; Soutar, I.; Swanson, L.; Geoghegan, M. Macromolecules 2008, 41, 2203−2211. (36) Buback, M.; Hesse, P.; Lacík, I. Macromol. Rapid Commun. 2007, 28, 2049−2054.

ness cluster Axelera is acknowledged. The authors thank Olivier Boyron (C2P2, LCPP Team) for his invaluable help concerning SEC analyses and Malvern Instrument for the technical support.

■

REFERENCES

(1) Thomas, R. J. Water Borne Coat. 1989, 12, 8−10. (2) Städler, B.; Price, A. D.; Zelikin, A. N. Adv. Funct. Mater. 2011, 21, 14−28. (3) Morishita, M.; Goto, T.; Takayama, K.; Peppas, N. A. J. Drug Delivery Sci. Technol. 2006, 16, 19−24. (4) Matyjaszewki, K.; Gnanou, Y.; Leibler, L. Macromolecular Engineering: Precise Synthesis, Materials Properties, Applications; WileyVCH: Weinheim, 2007. (5) Braunecker, W. A.; Matyjaszewski, K. Prog. Polym. Sci. 2007, 32, 93−146. (6) Chong, Y. K.; Le, T. P. T.; Moad, G.; Rizzardo, E.; Thang, S. H. Macromolecules 1999, 32, 2071−2074. (7) Yang, C.; Cheng, Y. L. J. Appl. Polym. Sci. 2006, 102, 1191−1201. (8) Hosseini Nejad, E.; Castignolles, P.; Gilbert, R. G.; Guillaneuf, Y. J. Polym. Sci., Part A: Polym. Chem. 2008, 46, 2277−2289. (9) Pelet, J. M.; Putnam, D. Macromolecules 2009, 42, 1494−1499. (10) Bertin, D.; Gigmes, D.; Marque, S. R. A.; Tordo, P. Chem. Soc. Rev. 2011, 40, 2189−2198. (11) Hawker, C. J.; Bosman, A. W.; Harth, E. Chem. Rev. 2001, 101, 3661−3688. (12) Guillaneuf, Y.; Gigmes, D.; Marque, S. R. A.; Astolfi, P.; Greci, L.; Tordo, P.; Bertin, D. Macromolecules 2007, 40, 3108−3114. (13) Charleux, B.; Nicolas, J.; Guerret, O. Macromolecules 2005, 38, 5485−5492. (14) Nicolas, J.; Dire, C.; Mueller, L.; Belleney, J.; Charleux, B.; Marque, S. R. A.; Bertin, D.; Magnet, S.; Couvreur, L. Macromolecules 2006, 39, 8274−8282. (15) Nicolas, J.; Brusseau, S.; Charleux, B. J. Polym. Sci., Part A: Polym. Chem. 2010, 48, 34−47. (16) Dire, C.; Magnet, S.; Couvreur, L.; Charleux, B. Macromolecules 2008, 42, 95−103. (17) Brusseau, S.; Belleney, J.; Magnet, S.; Couvreur, L.; Charleux, B. Polym. Chem. 2010, 1, 720−729. (18) Brusseau, S.; D’Agosto, F.; Magnet, S.; Couvreur, L.; Chamignon, C.; Charleux, B. Macromolecules 2011, 44, 5590−5598. (19) Matyjaszewski, K.; Xia, J. Chem. Rev. 2001, 101, 2921−2990. (20) Kamigaito, M.; Ando, T.; Sawamoto, M. Chem. Rev. 2001, 101, 3689−3746. (21) Ashford, E. J.; Naldi, V.; O’Dell, R.; Billingham, N. C.; Armes, S. P. Chem. Commun. 1999, 1285−1286. (22) Barner-Kowollik, C. Handbook of RAFT Polymerization; WileyVCH: Weinheim, 2008. (23) Chaduc, I.; Zhang, W.; Rieger, J.; Lansalot, M.; D’Agosto, F.; Charleux, B. Macromol. Rapid Commun. 2011, 32, 1270−1276. (24) Boursier, T.; Chaduc, I.; Rieger, J.; D’Agosto, F.; Lansalot, M.; Charleux, B. Polym. Chem. 2010, 2, 355−362. (25) Xu, X.; Smith, A. E.; Kirkland, S. E.; McCormick, C. L. Macromolecules 2008, 41, 8429−8435. (26) Couvreur, L.; Lefay, C.; Belleney, J.; Charleux, B.; Guerret, O.; Magnet, S. Macromolecules 2003, 36, 8260−8267. (27) Baussard, J.-F.; Habib-Jiwan, J.-L.; Laschewsky, A.; Mertoglu, M.; Storsberg, J. Polymer 2004, 45, 3615−3626. (28) Thomas, D. B.; Convertine, A. J.; Hester, R. D.; Lowe, A. B.; McCormick, C. L. Macromolecules 2004, 37, 1735−1741. (29) Kuchta, F.-D.; van Herk, A. M.; German, A. L. Macromolecules 2000, 33, 3641−3649. (30) Beuermann, S.; Buback, M.; Hesse, P.; Kukučková, S.; Lacık, I. Macromol. Symp. 2007, 248, 23−32. (31) Lacik, I.; Ucnova, L.; Kukučková, S.; Buback, M.; Hesse, P.; Beuermann, S. Macromolecules 2009, 42, 7753−7761. (32) Mukherjee, A. K.; Schmitz, K. S.; Bhuiyan, L. B. Langmuir 2004, 20, 11802−11810. 1247


RAFT Polymerization of Methacrylic Acid in Water - American

Recommend Documents