RAFT‐mediated batch emulsion polymerization of styrene using poly[N‐(4‐vinylbenzyl)‐N,N‐dibutylamine hydrochloride] trithiocarbonate as both surfactant and macro‐RAFT agent

Poly[N‐(4‐vinylbenzyl)‐N,N‐dibutylamine hydrochloride] trithiocarbonate, which contains the reactive trithiocarbonate group and the appending surface‐active groups, is used as both surfactant and macromolecular reversible addition‐fragmentation chain transfer (macro‐RAFT) agent in batch emulsion polymerization of styrene. Under the conditions at high monomer content of ～20 wt % and with the molecular weight of the macro‐RAFT agent ranging from 4.0 to 15.0 kg/mol, well‐controlled batch emulsion RAFT polymerization initiated by the hydrophilic 2‐2′‐azobis(2‐methylpropionamidine) dihydrochloride is achieved. The polymerization leads to formation of nano‐sized colloids of the poly[N‐(4‐vinylbenzyl)‐N,N‐dibutylamine hydrochloride]‐b‐ polystyrene‐b‐poly[N‐(4‐vinylbenzyl)‐N,N‐dibutylamine hydrochloride] triblock copolymer. The colloids generally have core‐shell structure, in which the hydrophilic block forms the shell and the hydrophobic block forms the core. The molecular weight of the triblock copolymer linearly increases with increase in the monomer conversion, and the values are well‐consistent with the theoretical ones. The molecular weight polydispersity index of the triblock copolymer is below 1.2 at most cases of polymerization. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Thermoresponsive diblock copolymer micellar macro‐RAFT agent‐mediated dispersion RAFT polymerization and synthesis of temperature‐sensitive ABC triblock copolymer nanoparticles

The micellar macro‐RAFT agent‐mediated dispersion polymerization of styrene in the methanol/water mixture is performed and synthesis of temperature‐sensitive ABC triblock copolymer nanoparticles is investigated. The thermoresponsive diblock copolymer of poly(N,N‐dimethylacrylamide)‐block‐poly[N‐(4‐vinylbenzyl)‐N,N‐diethylamine] trithiocarbonate forms micelles in the polymerization solvent at the polymerization temperature and, therefore, the dispersion RAFT polymerization undergoes as similarly as seeded dispersion polymerization with accelerated polymerization rate. With the progress of the RAFT polymerization, the molecular weight of the synthesized triblock copolymer of poly(N,N‐dimethylacrylamide)‐block‐poly[N‐(4‐vinylbenzyl)‐N,N‐diethylamine]‐b‐polystyrene linearly increases with the monomer conversion, and the PDI values of the triblock copolymers are below 1.2. The dispersion RAFT polymerization affords the in situ synthesis of the triblock copolymer nanoparticles, and the mean diameter of the triblock copolymer nanoparticles increases with the polymerization degree of the polystyrene block. The triblock copolymer nanoparticles contain a central thermoresponsive poly [N‐(4‐vinylbenzyl)‐N,N‐diethylamine] block, and the soluble‐to‐insoluble ‐‐transition temperature is dependent on the methanol content in the methanol/water mixture. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2155–2165     

Thermo‐ and pH‐induced self‐assembly of P(AA‐b‐NIPAAm‐b‐AA) triblock copolymers synthesized via RAFT polymerization

A series of environmentally sensitive ABA triblock copolymers with different block lengths were prepared by reversible addition‐fragmentation chain transfer (RAFT) polymerization from acrylic acid (AA) and N‐isopropylacrylamide (NIPAAm). The GPC and ¹H NMR analyses demonstrated the narrow molecular weight distribution and precise chemical structure of the prepared P(AA‐b‐NIPAAm‐b‐AA) triblock copolymers owing to the controlled/living characteristics of RAFT polymerization. The lower critical solution temperature (LCST) of the triblock copolymers could be tailored by adjusting the length of PAA block and controlled by the pH value. Under heating, the triblock copolymers underwent self‐assemble in dilute aqueous solution and formed nanoparticles revealed via TEM images. Physically crosslinked nanogels induced by inter‐/intra‐hydrogen bonding or core‐shell micelle particles thus could be obtained by changing environmental conditions. With a well‐defined structure and stimuli‐responsive properties, the P(AA‐b‐NIPAAm‐b‐AA) copolymer is expected to be employed as a nanocarrier for biomedical applications in controlled‐drug delivery and targeting therapy. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1109–1118     

An Emulsifier‐Free RAFT‐Mediated Process for the Efficient Synthesis of Cerium Oxide/Polymer Hybrid Latexes

Hybrid latexes based on cerium oxide nanoparticles are synthesized via an emulsifier‐free process of emulsion polymerization employing amphiphatic macro‐RAFT agents. Poly(butyl acrylate‐co‐acrylic acid) random oligomers of various compositions and chain lengths are first obtained by RAFT copolymerization in the presence of a trithiocarbonate as controlling agent. In a second step, the seeded emulsion copolymerization of styrene and methyl acrylate is carried out in the presence of nanoceria with macro‐RAFT agents adsorbed at their surface, resulting in a high incorporation efficiency of cerium oxide nanoparticles in the final hybrid latexes, as evidenced by cryo‐transmission electron microscopy.     

Synthesis of poly(n‐butyl acrylate) homopolymer and poly(styrene‐b‐n‐butyl acrylate‐b‐styrene) triblock copolymer via AGET emulsion ATRP using a cationic surfactant

Cationic emulsions of triblock copolymer particles comprising a poly(n‐butyl acrylate) (PⁿBA) central block and polystyrene (PS) outer blocks were synthesized by activator generated by electron transfer (AGET) atom transfer radical polymerization (ATRP). Difunctional ATRP initiator, ethylene bis(2‐bromoisobutyrate) (EBBiB), was used as initiator to synthesize the ABA type poly(styrene‐b‐n‐butyl acrylate‐b‐styrene) (PS‐PⁿBA‐PS) triblock copolymer. The effects of ligand and cationic surfactant on polymerizations were also discussed. Gel permeation chromatography (GPC) was used to characterize the molecular weight (M_n) and molecular weight distribution (MWD) of the resultant triblock copolymers. Particle size and particle size distribution of resulted latexes were characterized by dynamic light scattering (DLS). The resultant latexes showed good colloidal stability with average particle size around 100–300 nm in diameter. Glass transition temperature (T_g) of copolymers was studied by differential scanning calorimetry (DSC). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 611–620     

Influence of the stirring speed and CaCl2 concentration on the nano‐object morphologies obtained via RAFT‐mediated aqueous emulsion polymerization in the presence of a water‐soluble macroRAFT agent

Aqueous emulsion polymerizations of styrene were performed in the presence of a macromolecular reversible addition‐fragmentation chain transfer (RAFT) agent (macroRAFT) composed of acrylic acid (AA) and poly(ethylene oxide) methyl ether acrylate (PEOA), end‐capped by a reactive dodecyl trithiocarbonate group (P(AA‐co‐PEOA)‐TTC). The influence of the stirring speed or the presence of different amounts of a divalent salt, CaCl₂, were investigated in this polymerization‐induced self‐assembly process, in which spherical and nonspherical nano‐objects were formed upon the synthesis of amphiphilic diblock copolymers in situ. It appeared that the addition of CaCl₂ led to the controlled formation of different nano‐objects such as spheres, fibers or vesicles, whereas an appropriate stirring speed was required for the formation of nanofibers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Aqueous RAFT polymerization of N‐isopropylacrylamide‐mediated with hydrophilic macro‐RAFT agent: Homogeneous or heterogeneous polymerization?

Aqueous RAFT polymerization of N‐isopropylacrylamide (NIPAM) mediated with hydrophilic macro‐RAFT agent is generally used to prepare poly(N‐isopropylacrylamide) (PNIPAM)‐based block copolymer. Because of the phase transition temperature of the block copolymer in water being dependent on the chain length of the PNIPAM block, the aqueous RAFT polymerization is much more complex than expected. Herein, the aqueous RAFT polymerization of NIPAM in the presence of the hydrophilic macro‐RAFT agent of poly(dimethylacrylamide) trithiocarbonate is studied and compared with the homogeneous solution RAFT polymerization. This aqueous RAFT polymerization leads to the well‐defined poly(dimethylacrylamide)‐b‐poly(N‐isopropylacrylamide)‐b‐poly(dimethylacrylamide) (PDMA‐b‐PNIPAM‐b‐PDMA) triblock copolymer. It is found, when the triblock copolymer contains a short PNIPAM block, the aqueous RAFT polymerization undergoes just like the homogeneous one; whereas when the triblock copolymer contains a long PNIPAM block, both the initial homogeneous polymerization and the subsequent dispersion polymerization are involved and the two‐stage ln([M]_o/[M])‐time plots are indicated. The reason that the PNIPAM chain length greatly affects the aqueous RAFT polymerization is discussed. The present study is anticipated to be helpful to understand the chain extension of thermoresponsive block copolymer during aqueous RAFT polymerization. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis of anionic amphiphilic diblock copolymers of poly(styrene) and poly(acrylic acid) by reverse iodine transfer polymerization (RITP) in solution and emulsion

Reverse iodine transfer polymerization (RITP), offering the appealing potential of the in situ generation of transfer agents out of molecular iodine I₂, is employed in the synthesis of anionic amphiphilic diblock copolymers of poly(styrene) and poly(acrylic acid). Starting with well‐characterized poly(styrene) as macro‐transfer agents synthesized by RITP, diblock copolymers poly(styrene)‐b‐poly(tert‐butyl acrylate) of various lengths are successfully yielded in solution with a good architectural control. These blocks are then subjected to acid deprotection and subsequent pH control to give rise to anionic amphiphilic poly(styrene)‐b‐poly(acrylic acid). Besides, homopolymers of tert‐butyl acrylate are produced by RITP both in solution and in emulsion. Furthermore, a fruitful trial of the synthesis of diblock copolymers poly(tert‐butyl acrylate)‐b‐poly(styrene) is carried out through chain extension of the poly(tert‐butyl acrylate) latex as a macro‐transfer agent in seeded emulsion polymerization of styrene. Finally, the prepared block copolymer is deprotected to bring about its amphiphilic nature and a pH control caters for its anionic character. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4389–4398     

Formation of triblock copolymers via a tandem enhanced spin capturing—nitroxide‐mediated polymerization reaction sequence

The preparation of ABA‐type block copolymers via tandem enhanced spin capturing polymerization (ESCP) and nitroxide‐mediated polymerization (NMP) processes is explored in‐depth. Midchain alkoxyamine functional polystyrenes (M_n = 6200, 12,500 and 19,900 g mol^?1) were chain extended with styrene as well as tert‐butyl acrylate at elevated temperature NMP conditions (T = 110 °C) generating a tandem ESCP‐NMP sequence. Although the chain extensions and thus the block copolymer formation processes function well (yielding in the case of the chain extension with styrene number average molecular weights of up to 20,800 g mol^?1 (PDI = 1.22) when the 6200 g mol^?1 precursor is used and up to 67,500 g mol^?1 (PDI = 1.36) when the 19,900 g mol^?1 precursor is used and 21,600 g mol^?1 (PDI = 1.17) as well as 37,100 g mol^?1 (PDI = 1.21) for the tert‐butyl acrylate chain extensions for the 6200 and 12,500 g mol^?1 precursors, respectively), it is also evident that the efficiency of the block copolymer formation process decreases with an increasing chain length of the ESCP precursor macromolecules (i.e., for the 19,900 g mol^?1 ESCP precursor no efficient chain extension with tert‐butyl acrylate can be observed). For the polystyrene‐block‐tert‐butyl acrylate‐block‐polystyrene polymers, the molecular weights were determined via triple detection SEC using light scattering and small‐angle X‐ray scattering. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

A facile “graft from” method to prepare molecular‐level dispersed graphene–polymer composites

Graphene–polymer composites of positive‐charged poly(dimethyl aminoethyl acrylate), negative‐charged poly(acrylic acid), and neutral polystyrene were prepared by “graft from” methodology using reversible addition fragmentation chain transfer (RAFT) polymerization via a pyrene functional RAFT agent (PFRA) modified graphene precursor. Fluorescence spectroscopy and attenuated total reflection infrared (ATR‐IR) evidenced that the PFRA was attached on the graphene basal planes by π–π stacking interactions, which is strong enough to anti‐dissociation in the polymerization mixture up to 80°C. Atomic force microscopy (AFM) revealed that the thickness of a graphene–polymer sheet was about 4.0 nm. Graphene composites of different polymers with the same polymerization degree exhibited similar conductivity; however, when the polymer chain was designed as random copolymer the conductivity was significantly decreased. It was also observed that the longer the grafted polymer chains the lower the conductivity. ATR‐IR spectroscopy and thermogravimetric analysis were also performed to characterize the as‐prepared composites. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis,surface properties,and morphologies of poly[methyl(3,3,3‐trifluoropropyl)siloxane]‐b‐polystyrene‐b‐poly(tert‐butyl acrylate) triblock copolymers by a combination of anionic ROP and ATRP

A series of well‐defined poly[methyl(3,3,3‐trifluoropropyl)siloxane]‐b‐polystyrene‐b‐poly(tert‐butyl acrylate) (PMTFPS‐b‐PS‐b‐PtBA) triblock copolymers were prepared by a combination of anionic ring‐opening polymerization of 1,3,5‐trimethyl‐1,3,5‐tris(3′,3′,3′‐trifluoropropyl)cyclotrisiloxane (F₃), and atom transfer radical polymerization (ATRP) of styrene (St) and tert‐butyl acrylate (tBA), using the obtained α‐bromoisobutyryl‐terminal PMTFPS (PMTFPS‐Br) as the macroinitiators. The ATRP of St from PMTFPS‐Br, as well as the ATRP of tBA from the obtained PMTFPS‐b‐PS‐Br macroinitiators, has typical characteristic of controlled/living polymerization. The results of contact angle measurements for the films of PMTFPS‐b‐PS‐b‐PtBA triblock copolymers demonstrate that the compositions have an effect on the wetting behavior of the copolymer films. For the copolymer films with different compositions, there may be different macroscale or nanoscale structures on the outmost layer of the copolymer surfaces. The films with high content of PtBA blocks exhibit almost no ordered microstructures on the outmost layer of the copolymer surfaces, even though they have microphase‐separated structures in bulk. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Ab initio RAFT emulsion polymerization of butadiene using the amphiphilic poly(acrylic acid‐b‐styrene) trithiocarbonate as both surfactant and mediator

Ab initio reversible addition fragmentation chain transfer (RAFT) emulsion polymerization of butadiene was investigated by using the amphiphilic poly(acrylic acid_n‐b‐styrene₅) trithiocarbonate as both surfactant and mediator. The neutralization on acrylic acid (AA) units played significant influence on the gelation. When half of the AA units were neutralized, the gelation occurred in the early stage of the polymerization so that the highest accessible molecular weight of polybutadiene was as low as 5 kg mol^?1. In the non‐neutralized conditions, the gelation was much retarded so that the highest accessible molecular weight was increased up to 23 kg mol^?1. In the non‐neutralized conditions, potassium persulfate could not initiate the polymerization. When azobisisobutyronitrile was used as initiator, the polymerization mediated by poly(acrylic acid₂₇‐b‐styrene₅) trithiocarbonate could proceed much faster than the solution polymerization did. The latex was stable. Before the gel point, molecular weight agreed well with the theoretical prediction while PDI was relatively high due to the branching reaction. The poly(butadiene‐b‐styrene) core/shell particles could obtained by extending polybutadiene. When the n value in poly (acrylic acid_n‐b‐styrene₅) trithiocarbonate was lower than 20, the coalescence would occur, leading to the formation of some coagulum. On the other hand, when n value was as high as 60, the molecular weight was out of control. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

The Effect of Hydrophile Topology in RAFT‐Mediated Polymerization‐Induced Self‐Assembly

Polymerization‐induced self‐assembly (PISA) was employed to compare the self‐assembly of different amphiphilic block copolymers. They were obtained by emulsion polymerization of styrene in water using hydrophilic poly(N‐acryloylmorpholine) (PNAM)‐based macromolecular RAFT agents with different structures. An average of three poly (ethylene glycol acrylate) (PEGA) units were introduced either at the beginning, statistically, or at the end of a PNAM backbone, resulting in formation of nanometric vesicles and spheres from the two former macroRAFT architectures, and large vesicles from the latter. Compared to the spheres obtained with a pure PNAM macroRAFT agent, composite macroRAFT architectures promoted a dramatic morphological change. The change was induced by the presence of PEGA hydrophilic side‐chains close to the hydrophobic polystyrene segment.     

Brush macro‐RAFT agent mediated dispersion polymerization of styrene in the alcohol/water mixture

Dispersion RAFT polymerization of styrene in the alcohol/water mixture mediated with the brush macro‐RAFT agent of poly[poly(ethylene oxide) methyl ether vinylphenyl‐co‐styrene] trithiocarbonate [P(mPEGV‐co‐St)‐TTC] with similar molecular weight but different chemical composition is investigated. Well‐controlled RAFT polymerization including an initial slow homogeneous polymerization and a subsequent fast heterogeneous polymerization at almost complete monomer conversion is achieved. The molecular weight of the synthesized block copolymer increases linearly with the monomer conversion, and the polydispersity is relatively narrow (PDI < 1.3). The RAFT polymerization kinetics is dependent on the chemical composition in the brush macro‐RAFT agents, and those with high content of hydrophobic segment lead to fast RAFT polymerization. The growth of the block copolymer nano‐objects during the RAFT polymerization is explored, and various block copolymer nano‐objects such as nanospheres, worms, vesicles and large‐compound‐micelle‐like particles are prepared. The parameters such as the chemical composition in the brush macro‐RAFT agent, the chain length of the solvatophobic block, the concentration of the feeding monomer and the solvent character affecting the size and morphology of the block copolymer nano‐objects are investigated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3177–3190     

Triblock copolymer synthesis via controlled radical polymerization in solution using S‐tert‐alkyl‐N,N‐alkoxycarbonylalkyldithiocarbamate RAFT agents

This paper presents the solution homopolymerization, random and block copolymerization of acrylic monomers, mediated using an S‐(1,4‐phenylenebis(propane‐2,2‐diyl)) bis(N,N‐butoxycarbonylmethyldithiocarbamate) RAFT agent. Fair to good control was obtained over the solution homopolymerization of various acrylic monomers. Although inhibition periods were observed, nearly no retardation was found to occur. Satisfactory control was also obtained over the solution copolymerization of n‐butyl acrylate with methacrylic acid, mediated using this RAFT agent. Finally, triblock copolymer synthesis, starting from the macromolecular intermediates produced in the homo‐ and copolymerization experiments, was studied, and was shown to be successful. The observed relatively broad molar mass distributions could be explained by a partial decomposition of the dithiocarbamate‐based RAFT agent during synthesis and/or polymerization, for which strong indications were obtained by performing a careful MALDI‐ToF MS analysis. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6419–6434, 2006     

Polymerization‐induced self‐assembly of block copolymer through dispersion RAFT polymerization in ionic liquid

Polymerization‐induced self‐assembly of block copolymer through dispersion RAFT polymerization has been demonstrated to be a valid method to prepare block copolymer nano‐objects. However, volatile solvents are generally involved in this preparation. Herein, the in situ synthesis of block copolymer nano‐objects of poly(ethylene glycol)‐block‐polystyrene (PEG‐b‐PS) in the ionic liquid of 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([BMIN][PF₆]) through the macro‐RAFT agent mediated dispersion polymerization is investigated. It is found that the dispersion RAFT polymerization of styrene in the ionic liquid of [BMIN][PF₆] runs faster than that in the alcoholic solvent, and the dispersion RAFT polymerization in the ionic liquid affords good control over the molecular weight and the molecular weight distribution of the PEG‐b‐PS diblock copolymer. The morphology of the in situ synthesized PEG‐b‐PS diblock copolymer nano‐objects, e.g., nanospheres and vesicles, in the ionic liquid is dependent on the polymerization degree of the solvophobic block and the concentration of the fed monomer, which is somewhat similar to those in alcoholic solvent. It is anticipated that the dispersion RAFT polymerization in ionic liquid broads a new way to prepare block copolymer nano‐objects. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1517–1525     

Polymer coating of graphene oxide via reversible addition–fragmentation chain transfer mediated emulsion polymerization

This work describes a versatile method to encapsulate graphene oxide (GO) with polymers using reversible addition‐fragmentation chain transfer (RAFT) mediated emulsion polymerization. A living low molecular weight anionic macro‐RAFT statistical copolymer of sodium styrene sulfonate, acrylic acid, and butyl acrylate (BA) was synthesized using 2‐{[(butylsulfanyl)carbonothioyl] sulfanyl} propanoic acid as the chain transfer agent. GO was dispersed in water by pretreating the surface with poly(allylamine hydrochloride) (PAH), before being stabilized by the addition of the anionic macro‐RAFT copolymer. PAH was used to facilitate the adsorption of the macro‐RAFT copolymer to the GO surface via electrostatic attraction between opposite charges. The dispersed GO sheets were encapsulated with polymer by the free radical emulsion polymerization of methyl methacrylate and BA under starved fed conditions. The polymer shells encapsulating the GO sheets were formed by the chain extension of the adsorbed living macro‐RAFT copolymer. TEM, SEM, FTIR, and AFM were used to confirm the presence of the polymer layer on the surface of the GO. The thickness of the polymer coating can be adjusted by controlling the amount of monomer fed into the system. Partial polymer coatings of the GO could be achieved by varying the amount of PAH. The encapsulated GO was found to be easily dispersed in both aqueous and organic solvents over a range of polarities. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1413–1421     

Hyperbranched polymers as scaffolds for multifunctional reversible addition–fragmentation chain‐transfer agents: A route to polystyrene‐core‐polyesters and polystyrene‐block‐poly(butyl acrylate)‐core‐polyesters

Polydisperse hyperbranched polyesters were modified for use as novel multifunctional reversible addition–fragmentation chain‐transfer (RAFT) agents. The polyester‐core‐based RAFT agents were subsequently employed to synthesize star polymers of n‐butyl acrylate and styrene with low polydispersity (polydispersity index < 1.3) in a living free‐radical process. Although the polyester‐core‐based RAFT agent mediated polymerization of n‐butyl acrylate displayed a linear evolution of the number‐average molecular weight (M_n) up to high monomer conversions (>70%) and molecular weights [M_n > 140,000 g mol^?1, linear poly(methyl methacrylate) equivalents)], the corresponding styrene‐based system reached a maximum molecular weight at low conversions (≈30%, M_n = 45,500 g mol^?1, linear polystyrene equivalents). The resulting star polymers were subsequently used as platforms for the preparation of star block copolymers of styrene and n‐butyl acrylate with a polyester core with low polydispersities (polydispersity index < 1.25). The generated polystyrene‐based star polymers were successfully cast into highly regular honeycomb‐structured microarrays. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3847–3861, 2003     

RAFT‐mediated emulsion polymerization of styrene using brush copolymer as surfactant macro‐RAFT agent: Effect of the brush copolymer sequence and chemical composition

The nonionic amphiphilic brush polymers such as poly[poly(ethylene oxide) methyl ether vinylphenyl‐co‐styrene] trithiocarbonate [P(mPEGV‐co‐St)‐TTC] and poly[poly(ethylene oxide) methyl ether vinylphenyl‐b‐styrene‐b‐poly(ethylene oxide) methyl ether vinylphenyl] trithiocarbonate [P(mPEGV‐b‐St‐b‐mPEGV)‐TTC] with different monomer sequence and chemical composition are synthesized and their application as macro‐RAFT agent in the emulsion RAFT polymerization of styrene is explored. It is found that the monomer sequence in the brush polymers exerts great influence on the emulsion RAFT polymerization kinetics, and the fast polymerization with short induction period in the presence of P(mPEGV‐co‐St)‐TTC is demonstrated. Besides, the chemical composition in the brush polymer macro‐RAFT agent effect on the emulsion RAFT polymerization is investigated, and the macro‐RAFT agent with high percent of the hydrophobic PS segment leads to fast and well controlled polymerization. The growth of triblock copolymer colloids in the emulsion polymerization is checked, and it reveals that the colloidal morphology is ascribed to the hydrophobic PS block extension, and the P(mPEGV‐co‐St) block almost have no influence just on the size of the colloids. This may be the first example to study the monomer sequence and the chemical composition in the macro‐RAFT agent on emulsion RAFT polymerization, and will be useful to reveal the block copolymer particle growth. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis and characterization of block copolymers containing poly(di(ethylene glycol) 2‐ethylhexyl ether acrylate) by reversible addition–fragmentation chain transfer polymerization

Reversible addition–fragmentation chain transfer (RAFT) polymerization has emerged as one of the important living radical polymerization techniques. Herein, we report the polymerization of di(ethylene glycol) 2‐ethylhexyl ether acrylate (DEHEA), a commercially‐available monomer consisting of an amphiphilic side chain, via RAFT by using bis(2‐propionic acid) trithiocarbonate as the chain transfer agent (CTA) and AIBN as the radical initiator, at 70 °C. The kinetics of DEHEA polymerization was also evaluated. Synthesis of well‐defined ABA triblock copolymers consisting of poly(tert‐butyl acrylate) (PtBA) or poly(octadecyl acrylate) (PODA) middle blocks were prepared from a PDEHEA macroCTA. By starting from a PtBA macroCTA, a BAB triblock copolymer with PDEHEA as the middle block was also readily prepared. These amphiphilic block copolymers with PDEHEA segments bearing unique amphiphilic side chains could potentially be used as the precursor components for construction of self‐assembled nanostructures. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5420–5430, 2007