AB‐ and ABC‐type di‐ and triblock copolymers of poly[styrene‐block‐(ε‐caprolactone)] and poly[styrene‐block‐(ε‐caprolactone)‐block‐lactide]: synthesis,characterization and thermal studies

Polystyrene terminated with benzyl alcohol units was employed as a macroinitiator for ring‐opening polymerization of ε‐caprolactone and L ‐lactide to yield AB‐ and ABC‐type block copolymers. Even though there are many reports on the diblock copolymers of poly(styrene‐block‐lactide) and poly(styrene‐block‐lactone), this is the first report on the poly(styrene‐block‐lactone‐block‐lactide) triblock copolymer consisting of two semicrystalline and degradable segments. The triblock copolymers exhibited twin melting behavior in differential scanning calorimetry (DSC) analysis with thermal transitions corresponding to each of the lactone and lactide blocks. The block derived from ε‐caprolactone also showed crystallization transitions upon cooling from the melt. In the DSC analysis, one of the triblock copolymers showed an exothermic transition well above the melting temperature upon cooling. Thermogravimetric analysis of these block copolymers showed a two‐step degradation curve for the diblock copolymer and a three‐step degradation for the triblock copolymer with each of the degradation steps associated with each segment of the block copolymers. The present study shows that it is possible to make pure triblock copolymers with two semicrystalline segments which also consist of degradable blocks. Copyright © 2009 Society of Chemical Industry     

Synthesis and characterization of poly(n‐butyl methacrylate)‐b‐polystyrene diblock copolymers by atom transfer radical emulsion polymerization

Poly(n‐butyl methacrylate) (PBMA)‐b‐polystyrene (PSt) diblock copolymers were synthesized by emulsion atom transfer radical polymerization (ATRP). PBMA macroinitiators that contained alkyl bromide end groups were obtained by the emulsion ATRP of n‐butyl methacrylate with BrCH₃CHCOOC₂H₅ as the initiator; these were used to initiate the ATRP of styrene (St). The latter procedure was carried out at 85°C with CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine as the catalyst and polyoxyethylene(23) lauryl ether as the surfactant. With this technique, PBMA‐b‐PSt diblock copolymers were synthesized. The polymerization was nearly controlled; the ATRP of St from the macroinitiators showed linear increases in number‐average molecular weight with conversion. The block copolymers were characterized with IR spectroscopy, ¹H‐NMR, and differential scanning calorimetry. The effects of the molecular weight of the macroinitiators, macroinitiator concentration, catalyst concentration, surfactant concentration, and temperature on the polymerization were also investigated. Thermodynamic data and activation parameters for the ATRP are also reported. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2123–2129, 2005     

Synthesis and characterization of Pst‐b‐PDMS‐b‐PSt copolymers by atom transfer radical polymerization

Polystyrene‐b‐poly(dimethylsiloxane)‐b‐polystyrene (Pst‐b‐PDMS‐b‐PSt) triblock copolymers were synthesized by atom transfer radical polymerization (ATRP). Commercially available difunctional PDMS containing vinylsilyl terminal species was reacted with hydrogen bromide, resulting in the PDMS macroinitiators for the ATRP of styrene (St). The latter procedure was carried out at 130°C in a phenyl ether solution with CuCl and 4, 4′‐di (5‐nonyl)‐2,2′‐bipyridine (dNbpy) as the catalyzing system. By using this technique, triblock copolymers consisting of a PDMS center block and polystyrene terminal blocks were synthesized. The polymerization was controllable; ATRP of St from those macroinitiators showed linear increases in M_n with conversion. The block copolymers were characterized with IR and ¹H‐NMR. The effects of molecular weight of macroinitiators, macroinitiator concentration, catalyst concentration, and temperature on the polymerization were also investigated. Thermodynamic data and activation parameters for the ATRP are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3764–3770, 2004     

Synthesis of poly(fluorinated styrene)‐block‐poly(ethylene oxide) amphiphilic copolymers via atom transfer radical polymerization: potential application as paper coating materials

BACKGROUND: The surface of a substrate which comprises a fibrous material is brought into contact with a type of amphiphilic block copolymer which comprises hydrophilic/hydrophobic polymeric blocks. These amphiphilic copolymers have been synthesized by atom transfer radical polymerization (ATRP) technique. The atom transfer radical polymerization of poly(2,3,4,5,6‐pentafluorostyrene)‐block‐poly(ethylene oxide) (PFS‐b‐PEO) copolymers (di‐ and triblock structures) with various ranges of PEO molecular weights was initiated by a PEO chloro‐telechelic macroinitiator. The polymerization, carried out in bulk and catalysed by copper(I) chloride in the presence of 2,2′‐bipyridine ligand, led to A–B–A amphiphilic triblock and A–B amphiphilic diblock structures. RESULTS: With most of the macroinitiators, the living nature of the polymerizations led to block copolymers with narrow molecular weight distributions (1.09 < M_w/M_n < 1.33) and well‐controlled molecular structures. These block copolymers turned out to be water‐soluble through adjustment of the PEO block content (>90 wt%). Of all the block copolymers synthesized, PFS‐b‐PEO(10k)‐b‐PFS containing 10 wt% PFS was found to retard water absorption considerably. CONCLUSION: The printability of paper treated with the copolymers was evaluated with contact angle measurements and felt pen tests. The adsorption of such copolymers at the solid/liquid interface is relevant to the wetting and spreading of liquids on hydrophobic/hydrophilic surfaces. Copyright © 2009 Society of Chemical Industry     

AB,BAB and (AB)3 poly(ε‐caprolactone)‐based block copolymers with functionalized poly(meth)acrylate segments

Linear and star‐shaped poly(ε‐caprolactone) (PCL) block copolymers containing poly(meth)acrylate segments with glycidyl, 2‐(trimethylsilyloxy)ethyl and tert‐butyl pendant groups were synthesized using mono‐, di‐ and trifunctional PCL macroinitiators and appropriate (meth)acrylate monomers by controlled radical polymerization. The well‐defined structures with narrow molecular weight distributions indicate the coexistence of semi‐crystalline PCL and amorphous poly(meth)acrylic phases. The hydrophobic nature of the block copolymers can be easily converted to amphiphilic, which with biodegradable and biocompatible PCL segments are promising as polymeric carriers in drug delivery systems. © 2012 Society of Chemical Industry     

Synthesis of defined polyhedral oligosilsesquioxane‐containing diblock and triblock methacrylate copolymers by atom transfer radical polymerization

Defined diblock and triblock copolymers composed of methyl methacrylate‐co‐glycidyl methacrylate block and 3‐{3,5,7,9,11,13,15‐hepta(2‐methylpropyl)‐pentacyclo[9.5.1.1^3,9.1^5,15.1^7,13]‐octasiloxan‐1‐yl}propyl methacrylate block(s), i.e., P(MMA‐co‐GMA)‐b‐PiBuPOSSMA and PiBuPOSSMA‐b‐P(MMA‐co‐GMA)‐b‐PiBuPOSSMA, were synthesized by atom transfer radical polymerization (ATRP). First, monofunctional and bifunctional P(MMA‐co‐GMA) copolymers were synthesized by ATRP. Subsequently, these copolymers were successfully used as macroinitiators for ATRP of POSS‐containing methacrylate monomer. The process showed high initiation efficiency of macroinitiators and led to products with low dispersity. The synthesized block copolymers were characterized by size exclusion chromatography, ¹H‐NMR spectroscopy and their glass transition temperatures were determined by differential scanning calorimetry. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of PBMA‐b‐PSt‐b‐PBMA triblock copolymers by atom transfer radical emulsion polymerization

Poly(n‐butyl methacrylate)‐b‐polystyrene‐b‐poly(n‐butyl methacrylate) (PBMA‐b‐PSt‐b‐PBMA) triblock copolymers were successfully synthesized by emulsion atom transfer radical polymerization (ATRP). Difunctional polystyrene (PSt) macroinitiators that contained alkyl chloride end‐groups were prepared by ATRP of styrene (St) with CCl₄ as initiator and were used to initiate the ATRP of butyl methacrylate (BMA). The latter procedure was carried out at 85°C with CuCl/4,4′‐di (5‐nonyl)‐2,2′‐bipyridine (dNbpy) as catalyst and polyoxyethylene (23) lauryl ether (Brij35) as surfactant. Using this technique, triblock copolymers consisting of a PSt center block and PBMA terminal blocks were synthesized. The polymerization was nearly controlled, ATRP of St from those macroinitiators showed linear increases in the number average molecular weight (Mn) with conversion. The block copolymers were characterized with infrared (IR) spectroscopy, hydrogen‐1 nuclear magnetic resonance (¹HNMR), and differential scanning calorimetry (DSC). The effects of the molecular weight of macroinitiators, concentration of macroinitiator, catalyst, emulsion, and temperature on the polymerization were also investigated. Thermodynamic data and activation parameters for the ATRP were also reported. POLYM. ENG. SCI., 45:1508–1514, 2005. © 2005 Society of Plastics Engineers     

Nitroxide‐mediated ‘living’ free radical synthesis of novel rod–coil diblock copolymers with polystyrene and mesogen‐jacketed liquid‐crystal polymer segments

The synthesis of rod–coil diblock copolymers with narrow polydispersity was achieved for the first time by TEMPO‐mediated ‘living’ free radical polymerization of styrene and 2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene. The block architecture of the two diblock copolymers thus prepared, MPCS‐block‐St (5400/2400) and MPCS‐block‐St (10 800/8700), was confirmed by GPC, ¹H and ¹³C NMR and DSC studies. The liquid‐crystalline behaviour of the copolymers was studied by DSC and polarized optical microscope. It was observed that both copolymers showed two distinct glass transitions, corresponding to polystyrene and poly(‐2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene). Above the glass transition temperature of rigid block, liquid‐crystalline phase was formed. The clearing point of the phase is higher than the polymer decomposition temperature. © 2000 Society of Chemical Industry     

Synthesis and properties of hydrophilic segmented block copolymers based on poly(ethylene oxide)‐ran‐poly(propylene oxide)

The present article discusses the synthesis and various properties of segmented block copolymers with random copolymer segments of poly(ethylene oxide) and poly(propylene oxide) (PEO‐r‐PPO) together with monodisperse amide segments. The PEO‐r‐PPO contained 25 wt % PPO units and the segment presented a molecular weight of 2500 g/mol. The synthesized copolymers were analyzed by differential scanning calorimetry, Fourier transform infra‐red spectroscopy, atomic force microscopy and dynamic mechanical thermal analysis. In addition, the hydrophilicity and the contact angles (CAs) were studied. The PEO‐r‐PPO segments displayed a single low glass transition temperature, as well as a low PEO crystallinity and melting temperature, which gave enhanced low‐temperature properties of the copolymer. The water absorption values remained high. In comparison to mixtures of PEO/PPO segments, the random dispersion of PPO units in the PEO segments was more effective in reducing the PEO crystallinity and melting temperature, without affecting the hydrophilicity. Increasing the polyether segment length with terephthalic groups from 2500 to 10,000 g/mol increased the hydrophilicity and the room temperature elasticity. Furthermore, the CAs were found to be low 22–39° and changed with the crosslink density. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117:1394–1404, 2010     

Preparation and morphology of amphiphilic polystyrene–poly (2‐vinylpyridine) heteroarm star copolymers prepared by ATRP

BACKGROUND: The self‐assembly of amphiphilic copolymers has been demonstrated to be a powerful route towards supramolecular objects with novel architectures, functions and physical properties. In this study, the synthesis and morphology of amphiphilic linear polystyrene (PS)‐block‐poly(2‐vinylpyridine) (P2VP) and heteroarm star PS‐star‐P2VP copolymers are studied. The dispersion of silver nanoparticles with the prepared PS‐block‐P2VP and PS‐star‐P2VP copolymers is also discussed. RESULTS: Amphiphilic copolymers with different P2VP chain lengths were successfully synthesized using atom transfer radical polymerization (ATRP). The copolymers prepared had low polydispersity indices. Various aggregate morphologies, including spheres, vesicles, rods, large compound micelles, two‐dimensional ring‐like and three‐dimensional hollow structures, were formed by varying the hydrophilic coil length and the selective solvent content. Silver nanoparticles showed good dispersion behavior in both types of copolymers. CONCLUSION: Based on this study, it will be possible to prepare metal/copolymer nanocomposites by direct mixing. Further, the PS‐block‐P2VP and PS‐star‐P2VP copolymers prepared can be used in the preparation of nanoporous films as templates and nanoparticles as nanoreactors. They can also be applied in terms of oil recovery, paints and cosmetics formulations, as well as in pharmaceutical and medical applications as rheological agents. Copyright © 2008 Society of Chemical Industry     

Synthesis and characterization of degradable triarm low unsaturated poly(propylene oxide)‐block‐polylactide copolymers

A series of novel degradable triarm poly(propylene oxide)‐block‐polylactide (PPO‐b‐PLA) copolymers was synthesized by ring‐opening polymerization of L ‐lactide (LLA) or D ,L ‐lactide (DLLA) using low unsaturated PPO triols as macromolecular initiator. The chemical structures of the resulting copolymers were characterized by Fourier transform infrared (FTIR), gel permeation chromatography (GPC), and proton nuclear magnetic resonance (¹H‐NMR) spectroscopy. Combination of FTIR, GPC, and NMR results confirmed the formation of PPO‐b‐PLA copolymers. One glass transition was observed by differential scanning calorimetry (DSC), suggesting good miscibility between PPO and PLA segments in the copolymers. DSC and wide‐angle X‐ray diffraction demonstrated that PPO‐b‐PLLA copolymers were semicrystalline materials, and the crystallinity increased with increasing the PLLA content. In contrast, PPO‐b‐PDLLA copolymers were totally amorphous. The PPO‐b‐PLA copolymers exhibited improved thermal stability when compared with PPO polyols according to thermogravimetric analysis. The thermal degradation behavior of the copolymers depended on the composition. Polyurethane foams were prepared by crosslinking PPO and PPO‐b‐PLA copolymers using isocyanate. Alkaline degradation of the foams was investigated in 10 wt/vol % NaOH at 80°C. The results show that the novel PPO‐b‐PLA copolymers could be promising as degradable polymeric materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and surface properties of polydimethylsiloxane‐based block copolymers: poly[dimethylsiloxane‐block‐ (ethyl methacrylate)] and poly[dimethylsiloxane‐block‐(hydroxyethyl methacrylate)]

A polydimethylsiloxane (PDMS) macroazoinitiator was synthesized from bis(hydroxyalkyl)‐terminated PDMS and 4,4′‐azobis‐4‐cyanopentanoic acid by a condensation reaction. The bifunctional macroinitiator was used for the block copolymerization of ethyl methacrylate (EMA) and 2‐(trimethylsilyloxy)ethyl methacrylate (TMSHEMA) monomers. The poly(DMS‐block‐EMA) and poly(DMS‐block‐TMSHEMA) copolymers thus obtained were characterized using Fourier transform infrared and ¹H NMR spectroscopy and differential scanning calorimetry. After the deprotection of trimethylsilyl groups, poly(DMS‐block‐HEMA) and poly(DMS‐block‐EMA) copolymer film surfaces were analysed using scanning electron microscopy and X‐ray photoelectron spectroscopy. The effects of the PDMS concentration in the copolymers on both air and glass sides of films were examined. The PDMS segments oriented and moved to the glass side in poly(DMS‐block‐EMA) copolymer film while orientation to the air side became evident with increasing DMS content in poly(DMS‐block‐HEMA) copolymer film. The block copolymerization technique described here is a versatile and economic method and is also applicable to a wide range of monomers. The copolymers obtained have phase‐separated morphologies and the effects of DMS segments on copolymer film surfaces are different at the glass and air sides. Copyright © 2010 Society of Chemical Industry     

Hyperbranched homo and thermoresponsive graft copolymers by using ATRP‐macromonomer initiators

Macromonomer initiators behave as macro cross‐linkers, macro initiators, and macromonomers to obtain branched and cross‐linked block/graft copolymers. A series of new macromonomer initiators for atom transfer radical polymerization (MIM‐ATRP) based on polyethylene glycol (M_n = 495D, 2203D, and 4203D) (PEG) were synthesized by the reaction of the hydroxyl end of mono‐methacryloyl polyethylene glycol with 2‐bromo propanoyl chloride, leading to methacryloyl polyethylene glycol 2‐bromo propanoyl ester. Poly (ethylene glycol) functionalized with methacrylate at one end was reacted with 2‐bromopropionyl chloride to form a macromonomeric initiator for ATRP. ATRP was found to be a more controllable polymerization method than conventional free radical polymerization in view of fewer cross‐linked polymers and highly branched polymers produced from macromonomer initiators as well. In another scenario, ATRP of N‐isopropylacrylamide (NIPAM) was initiated by MIM‐ATRP to obtain PEG‐b‐PNIPAM branched block/graft copolymers. Thermal analysis, FTIR, ¹H NMR, TEM, and SEM techniques were used in the characterization of the products. They had a thermo‐responsive character and exhibited volume phase transition at ～ 36°C. A plasticizer effect of PEG in graft copolymers was also observed, indicating a lower glass transition temperature than that of pure PNIPAM. Homo and copolymerization kinetics were also evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of polystyrene‐b‐poly(ethylene oxide)‐b‐polystyrene triblock copolymers

A series of well‐defined and property‐controlled polystyrene (PS)‐b‐poly(ethylene oxide) (PEO)‐b‐polystyrene (PS) triblock copolymers were synthesized by atom‐transfer radical polymerization, using 2‐bromo‐propionate‐end‐group PEO 2000 as macroinitiatators. The structure of triblock copolymers was confirmed by ¹H‐NMR and GPC. The relationship between some properties and molecular weight of copolymers was studied. It was found that glass‐transition temperature (T_g) of copolymers gradually rose and crystallinity of copolymers regularly dropped when molecular weight of copolymers increased. The copolymers showed to be amphiphilic. Stable emulsions could form in water layer of copolymer–toluene–water system and the emulsifying abilities of copolymers slightly decreased when molecular weight of copolymers increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 727–730, 2006     

Synthesis and characterization of polystyrene‐b‐poly(ethylene oxide)‐b‐polystyrene triblock copolymers by atom‐transfer radical polymerization

Well‐defined polystyrene (PS)‐b‐poly(ethylene oxide) (PEO)‐b‐PS triblock copolymers were synthesized by atom‐transfer radical polymerization (ATRP), using C—X‐end‐group PEO as macroinitiators. The triblock copolymers were characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, and gel permeation chromatography. The experimental results showed that the polymerization was controlled/living. It was found that when the number‐average molecular weight of the macroinititors increased from 2000 to 10,000, the molecular weight distribution of the triblock copolymers decreased roughly from 1.49 to 1.07 and the rate of polymerization became much slower. The possible polymerization mechanism is discussed. According to the Cu content measured with atomic absorption spectrometry, the removal of catalysts, with CHCl₃ as the solvent and kaolin as the in situ absorption agent, was effective. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2882–2888, 2000     

Synthesis and characterization of four‐arm star‐shaped polymers and copolymers

Four‐arm star‐shaped polymers and copolymers were obtained by transition metal‐catalyzed atom‐transfer radical polymerization (ATRP). The polymers were characterized by FTIR and ¹H‐NMR spectroscopy. Gel permeation chromatography results indicated the formation of polystyrene and polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) arms with controlled molecular weights. In dilute solution, the linear polymers had higher inherent viscosities than star‐shaped ones. Thermogravimetric analysis showed a similar degradation mechanism for linear and star‐shaped polymers. Differential scanning calorimetry indicated the successful formation of diblock star‐shaped copolymers. Copyright © 2006 Society of Chemical Industry     

Synthesis of poly(paraphenylene vinylene)—polystyrene‐based rod‐coil block copolymer by atom transfer radical polymerization: Toward a self‐organized lamellar semiconducting material

Atom transfer radical polymerization (ATRP) was used as a versatile route to well‐defined poly(diethylhexyl‐p‐phenylenevinylene‐b‐styrene) (PPV‐b‐PS) semiconducting block copolymers. For this purpose, original conjugated macroinitiators were synthesized from DEH‐PPV and further used for the copolymerization reaction. The microphase‐separated morphologies obtained with the semiconducting PPV‐b‐PS block copolymer fulfill the basic structural requirements required to build efficient organic photovoltaic devices. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Architecture of rod consisting of hyperbranched pendant chains‐coil block copolymers by ATRP approach

Atom transfer radical polymerization (ATRP) was applied to a novel synthesis of rod consisting of hyperbranched pendant chains‐coil block copolymers. The procedure included the following steps: (1) esterification reaction of poly(ethylene glycol) methyl ether (PEO) with 2‐bromoisobutyryl bromide (BIBB) yielded a PEO‐Br macroinitiator, (2) ATRP method of 2‐hydroxylethyl methacrylate (HEMA) using PEO‐Br provided PEO‐block‐poly(2‐hydroxyethyl methacrylate) (PHEMA) block copolymers, (3) esterification of PEO‐block‐PHEMA with BIBB yielded block‐type polyinitiator, and (4) ATRP of HEMA‐Br inimer using block‐type polyinitiator provided coil‐rod (consisting of hyperbranched pendant chains) block copolymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of novel polystyrene‐block‐polyurethane‐block‐polystyrene tri‐block copolymers through atom transfer radical polymerization

Background: Radical polymerization is used widely to polymerize more than 70% of vinyl monomers in industry, but the control over molecular weight and end group of the resulting polymers is always a challenging task with this method. To prepare polymers with desired molecular weight and end groups, many controlled radical polymerization (CRP) ideas have been proposed over the last decade. Atom transfer radical polymerization (ATRP) is one of the successful CRP techniques. Using ATRP, there is no report on the synthesis of polystyrene‐block‐polyurethane‐block‐polystyrene (PSt‐b‐PU‐b‐PSt) tri‐block copolymers. Hence this paper describes the method of synthesizing these tri‐block copolymers. To accomplish this, first telechelic bromo‐terminated polyurethane was synthesized and used further to synthesize PSt‐b‐PU‐b‐PSt tri‐block copolymers using CuBr as a catalyst and N,N,N,N″,N″‐pentamethyldiethylenetriamine as a complexing agent. Results: The ‘living’ nature of the initiating system was confirmed by linear increase of number‐average molecular weight and conversion with time. A semi‐logarithmic kinetics plot shows that the concentration of propagating radical is steady. The results from nuclear magnetic resonance spectroscopy, gel permeation chromatography and differential scanning calorimetry show that the novel PSt‐b‐PU‐b‐PSt tri‐block copolymers were formed through the ATRP mechanism. Conclusion: For the first time, PSt‐b‐PU‐b‐PSt tri‐block copolymers were synthesized through ATRP. The advantage of this method is that the controlled incorporation of polystyrene block in polyurethane can be achieved by simply changing the polymerization time. Copyright © 2007 Society of Chemical Industry     

Synthesis and properties of amphiphilic star block copolymers with star macroinitiators based on a one‐pot approach

Previously, star polystyrenes (PSs) have been prepared by atom transfer radical polymerization (ATRP) of N‐[2‐(2‐bromoisobutyryloxy)ethyl]maleimide (BiBEMI) with a large excess of styrene (St) in one pot. But linear PSs were also present during the formation of the star polymers. In the work reported here, we found that control of the formation of star polymers using a one‐pot approach can be improved by using a two‐step process. The polymerization was conducted first at a low temperature to form multifunctional cores by copolymerization of BiBEMI and St. Second, on increasing the temperature, homopolymerization of St occurred to grow PS arms. Then a series of amphiphilic star polystyrene‐block‐poly(acrylic acid)s, (S₁₄A_x)₁₆, were prepared by ATRP of tert‐butyl acrylate with the star PSs as macroinitiators, followed by selective acidolysis of the poly(tert‐butyl acrylate) blocks. Their micellization was studied using dynamic light scattering, which suggested that (S₁₄A₁₁₂)₁₆ amphiphilic star block copolymers could form unimolecular micelles in a basic aqueous solution. Then pyrene molecules were encapsulated using the (S₁₄A₁₁₂)₁₆ amphiphilic star copolymers and the loading capacity was investigated with UV and fluorescence spectroscopy. © 2013 Society of Chemical Industry