Formation of Core‐Shell‐Corona Micellar Complexes through Adsorption of Double Hydrophilic Diblock Copolymers into Core‐Shell Micelles

Summary: The complexation between polystyrene‐block‐poly(acrylic acid) (PS‐b‐PAA) micelles and poly(ethylene glycol)‐block‐poly(4‐vinyl pyridine) (PEG‐b‐P4VP) is studied, and a facile strategy is proposed to prepare core‐shell‐corona micellar complexes. Micellization of PS‐b‐PAA in ethanol forms spherical core‐shell micelles with PS block as core and PAA block as shell. When PEG‐b‐P4VP is added into the core‐shell micellar solution, the P4VP block is absorbed into the core‐shell micelles to form spherical core‐shell‐corona micellar complexes with the PS block as core, the combined PAA/P4VP blocks as shell and the PEG block as corona. A model is suggested to characterize the core‐shell‐corona micellar complexes.

Schematic formation of core‐shell‐corona (CSC) micellar complexes by adsorption of PEG‐b‐P4VP into core‐shell PS‐b‐PAA micelles.     

Preparation of polymeric vesicles through ultrasonic treatment of poly(styrene‐block‐2‐vinylpyridine) micelles under alkaline conditions

An approach for the preparation of block copolymer vesicles through ultrasonic treatment of polystyrene‐block‐poly(2‐vinyl pyridine) (PS‐b‐P2VP) micelles under alkaline conditions is reported. PS‐b‐P2VP block copolymers in toluene, a selective solvent for PS, form spherical micelles. If a small amount of NaOH solution is added to the micelles solution during ultrasonic treatment, organic‐inorganic Janus‐like particles composed of the PS‐b‐P2VP block copolymers and NaOH are generated. After removal of NaOH, block copolymer vesicles are obtained. A possible mechanism for the morphological transition from spherical micelles to vesicles or Janus‐like particles is discussed. If the block copolymer micelles contain inorganic precursors, such as FeCl₃, hybrid vesicles are formed, which may be useful as biological and chemical sensors or nanostructured templates. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 953–959     

Self‐assembly of a triblock terpolymer mediated by hydrogen‐bonded complexes

A poly(methyl methacrylate)‐block‐poly(4‐vinylpyridine)‐block‐polystyrene (PMMA‐b‐P4VP‐b‐PS) triblock terpolymer is synthesized by ATRP to study its self‐assembly with PAA in organic solvents. The self‐assembly behavior of this system is compared with the one of a mixture of two diblocks, namely polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) and poly(methyl methacrylate)‐block‐poly(methacrylic acid) (PMMA‐b‐PMAA). For both systems, formation of hydrogen‐bonded complexes between the P4VP and PMAA or PAA blocks occurs. These complexes become insoluble in the solvent used and micelles with a P4VP/P(M)AA complexes core surrounded by PS and PMMA coronal chains are obtained in both cases. These micelles are analyzed by DLS and TEM. Spherical micelles are formed for both systems but the hydrodynamic radii obtained for the two types of micelles are different. Indeed, the micelles formed by the PMMA‐b‐P4VP‐b‐PS + PAA system are smaller than those observed for the PS‐b‐P4VP + PMMA‐b‐PMAA system. Finally, the effect of the molar ratio of the P4VP/PMAA complexing blocks is investigated. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 459–467     

Self‐assembly of thermo‐ and pH‐responsive poly(acrylic acid)‐b‐poly(N‐isopropylacrylamide) micelles for drug delivery

Self‐assembled thermo‐ and pH‐responsive poly(acrylic acid)‐b‐poly(N‐isopropylacrylamide) (PAA‐b‐PNIPAM) micelles for entrapment and release of doxorubicin (DOX) was described. Block copolymer PAA‐b‐PNIPAM associated into core‐shell micelles in aqueous solution with collapsed PNIPAM block or protonated PAA block as the core on changing temperature or pH. Complexation of DOX with PAA‐b‐PNIPAM triggered by the electrostatic interaction and release of DOX from the complexes due to the changing of pH or temperature were studied. Complex micelles incorporated with DOX exhibited pH‐responsive and thermoresponsive drug release profile. The release of DOX from micelles was suppressed at pH 7.2 and accelerated at pH 4.0 due to the protonation of carboxyl groups. Furthermore, the cumulative release of DOX from complex micelles was enhanced around LCST ascribed to the structure deformation of the micelles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5028–5035, 2008     

Double‐hydrophilic block copolymer for encapsulation and two‐way pH change‐induced release of metalloporphyrins

A double hydrophilic block copolymer composed of poly(acrylic acid) (PAA) and poly(4‐vinyl pyridine) (P4VP) was obtained through hydrolysis of diblock copolymer of poly(tert‐butyl acrylate) (PtBA) and P4VP synthesized using atom transfer radical polymerization. Water‐soluble micelles with PAA core and P4VP corona were observed at low (acidic) pH, while micelles with P4VP core and PAA corona were formed at high (basic) pH. Two metalloporphyrins, zinc tetraphenylporphyrin (ZnTPP) and cobalt tetraphenylporphyrin (CoTPP), were used as model compounds to investigate the encapsulation of hydrophobic molecules by both types of micelles. UV–vis spectroscopic measurements indicate that micelles with P4VP core are able to entrap more ZnTPP and CoTPP as a result of the axial coordination between the transition metals and the pyridine groups. The study found that metalloporphyrins encapsulated by the micelles with PAA core could be released on pH increase, while those entrapped by the micelles with P4VP core could be released on pH decrease. This behavior originates from the two‐way pH change‐induced disruption of PAA‐b‐P4VP micelles. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1734–1744, 2006     

Competitive hydrogen bonding and self‐assembly in poly(2‐vinyl pyridine)‐block‐poly(methyl methacrylate)/poly(hydroxyether of bisphenol A) blends

Blends of poly(2‐vinyl pyridine)‐block‐poly(methyl methacrylate) (P2VP‐b‐PMMA) and poly(hydroxyether of bisphenol A) (phenoxy) were prepared by solvent casting from chloroform solution. The specific interactions, phase behavior and nanostructure morphologies of these blends were investigated by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), dynamic light scattering (DLS), atomic force microscopy (AFM), and transmission electron microscopy (TEM). In this block copolymer/homopolymer blend system, it is established that competitive hydrogen bonding exists as both blocks of the P2VP‐b‐PMMA are capable of forming intermolecular hydrogen bonds with phenoxy. It was observed that the interaction between phenoxy and P2VP is stronger than that between phenoxy and PMMA. This imbalance in the intermolecular interactions and the repulsions between the two blocks of the diblock copolymer lead to a variety of phase morphologies. At low phenoxy concentration, spherical micelles are observed. As the concentration increases, PMMA begins to interact with phenoxy, leading to the changes of morphology from spherical to wormlike micelles and finally forms a homogenous system. A model is proposed to describe the self‐assembled nanostructures of the P2VP‐b‐PMMA/phenoxy blends, and the competitive hydrogen bonding is responsible for the morphological changes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1894–1905, 2009     

Tunable morphologies of rhenium complex‐containing polystyrene‐block‐poly(2‐vinylpyridine) aggregates

Polystyrene‐block‐poly(2‐vinylpyridine) (PS‐b‐P2VP) diblock copolymer was functionalized with luminescent chlorotricarbonyl rhenium (I) phenanthroline complex in the presence of silver perchlorate. The copolymer‐metal complex showed high sensitivity to the solvent system. Different morphologies and dimensions of the rhenium complex within nanosized micelles were controlled by changing the solvent systems. Core‐embedded rhenium complex within micelles appear by adding methanol, a poor solvent for the copolymer‐metal complex, to the solution of common solvent tetrahydrofuran (THF); the number of the core‐embedded rhenium complex and the scale of the micelles are strongly related to the addition of methanol. Moreover, a novel morphology of corona‐embedded rhenium complex micelles was prepared by dropping the original THF solution of copolymer‐metal complex into water at a low pH value. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2047–2053, 2008     

Synthesis of poly(2‐vinyl pyridine)‐b‐poly(n‐hexyl isocyanate) amphiphilic coil‐rod block copolymer by anionic polymerization

A well‐defined amphiphilic coil‐rod block copolymer, poly(2‐vinyl pyridine)‐b‐poly(n‐hexyl isocyanate) (P2VP‐b‐PHIC), was synthesized with quantitative yields by anionic polymerization. A low reactive one‐directional initiator, potassium diphenyl methane (DPM‐K), was very effective in polymerizing 2‐vinyl pyridine (2VP) without side reactions, leading to perfect control over molecular weight and molecular weight distribution over a broad range of initiator and monomer concentration. Copolymerization of 2VP with n‐hexyl isocyanate (HIC) was carried out in the presence of sodium tetraphenyl borate (NaBPh₄) to prevent backbiting reactions during isocyanate polymerization. Terminating the living end with a suitable end‐capping agent resulted in a P2VP‐b‐PHIC coil‐rod block copolymer with controlled molecular weight and narrow molecular weight distribution. Cast film from a chloroform solution of P2VP‐b‐PHIC displayed microphase separation, characteristic of coil‐rod block copolymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 607–615, 2005     

Synthesis of arborescent polystyrene‐g‐[poly(2‐vinylpyridine)‐b‐polystyrene] core–shell–corona copolymers

Arborescent copolymers with a core‐shell‐corona (CSC) architecture, incorporating a polystyrene (PS) core, an inner shell of poly(2‐vinylpyridine), P2VP, and a corona of PS chains, were obtained by anionic polymerization and grafting. Living PS‐b‐P2VP‐Li block copolymers serving as side chains were obtained by capping polystyryllithium with 1,1‐diphenylethylene before adding 2‐vinylpyridine. A linear or arborescent (generation G0 – G3) PS substrate, randomly functionalized with acetyl or chloromethyl coupling sites, was then added to the PS‐b‐P2VP‐Li solution for the grafting reaction. The grafting yield and the coupling efficiency observed in the synthesis of the arborescent PS‐g‐(P2VP‐b‐PS) copolymers were much lower than for analogous coupling reactions previously used to synthesize arborescent PS homopolymers and PS‐g‐P2VP copolymers from the same types of coupling sites. It was determined from static and dynamic light scattering analysis that PS‐b‐P2VP formed aggregates in THF, the solvent used for the synthesis. This presumably hindered coupling of the macroanions with the substrate, and explains the low grafting yield and coupling efficiency observed in these reactions. Purification of the crude products was also problematic due to the amphipolar character of the CSC copolymers and the block copolymer contaminant. A new fractionation method by cloud‐point centrifugation was developed to purify copolymers of generations G1 and above. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1075–1085     

Linear pentablock quintopolymers (l‐SIDMV) with five incompatible blocks: Polystyrene,polyisoprene‐1,4, poly(dimethylsiloxane), poly(tert‐butyl methacrylate), and poly(2‐vinylpyridine)

Three linear pentablock quintopolymers (l‐SIDMV), where S is polystyrene (PS), I polyisoprene‐1,4 (PI), D poly(dimethylsiloxane) (PDMS), M poly(tert‐butyl methacrylate) (PtBuM), and V poly(2‐vinylpyridine) (P2VP), were synthesized by anionic polymerization high vacuum techniques. The approach involves the following: (a) The synthesis of living triblock terpolymer PS‐b‐PI‐b‐PDMSLi and diblock copolymer P2VP‐b‐PtBuMK by sequential polymerizations of the corresponding monomers with sec‐BuLi and benzyl potassium, respectively; and (b) The selective linking of the living triblock terpolymer with the chlorosilane group of 2‐(chloromethylphenyl)ethyldimethylchlorosilane (CMPDMS), followed by linking of the living block copolymer with the remaining chloromethyl group of CMPDMS. Molecular characterization carried out by size exclusion chromatography, membrane osmometry, solution (in CDCl₃ or d₈‐toluene) and solid‐state ¹H‐NMR spectroscopy indicated a high degree of molecular and compositional homogeneity. Differential scanning calorimetry results on the precursors and final polymers were discussed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3938–3946, 2008     

Ultrathin and Large‐area Macroporous Polymeric Membranes Formed Through Self‐assembly of Sub‐10 nm Elastic Nanoparticles

A variety of sub‐10 nm nanoparticles are successfully prepared by crosslinking of polystyrene‐b‐poly(1,3‐butadiene) (PS‐b‐PB) and polystyrene‐b‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) block copolymer micelles and inverse micelles. Among them, the core‐crosslinked PS‐b‐PB micelles can self‐assemble into ultrathin (< 10 nm) macroporous (pore size <1 µm) membranes in a facile way, i.e., by simply drop‐coating the particle solution onto a mica surface. No continuous/porous membranes are produced from shell‐crosslinked PS‐b‐PB micelles and both forms of PS‐b‐P4VP micelles. This suggests that the unique structure of the block copolymer precursor, including the very flexible core‐forming block and the glassy corona‐forming block and the specific block length ratio, directly determines the formation of the macroporous membrane.

     

Synthesis and characterization of pH sensitive poly(glycidol)‐b‐poly(4‐vinylpyridine) block copolymers

Block copolymers of poly(glycidol)‐b‐poly(4‐vinylpyridine) were obtained by ATRP of 4‐vinylpyridine initiated by ω‐(2‐chloropropionyl) poly(glycidol) macroinitiators. By changing the monomer/macroinitiator ratio in the synthesis polymers with varied P4VP/PGl molar ratio were obtained. The obtained block copolymers showed pH sensitive solubility. It was found that the linkage of a hydrophilic poly(glycidol) block to a P4VP influenced the pK_a value of P4VP. DLS measurements showed the formation of fully collapsed aggregates exceeding pH 4.7. Above this pH values the collapsed P4VP core of the aggregates was stabilized by a surrounding hydrophilic poly(glycidol) corona. The size of the aggregates depended significantly upon the composition of the block copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1782–1794, 2009     

End‐group modification of poly(2,6‐dimethyl‐1,4‐phenylene ether) and in situ synthesis of poly(2,6‐dimethyl‐1,4‐phenylene ether)‐b‐poly(ethylene terephthalate) block copolymer

The preparation of poly(2,6‐dimethyl‐1,4‐phenylene ether)‐b‐poly(ethylene terephthalate) block copolymer was performed by the reaction of the 2‐hydroxyethyl modified poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPE‐EtOH) with poly(ethylene terephthalate) (PET) by an in situ process, during the synthesis of the polyester. The yield of the reaction of the 2‐hydroxyethyl functionalized PPE‐EtOH with PET was close to 100%. A significant proportion of the PET‐b‐PPE‐EtOH block copolymer was found to have short PET block. Nevertheless, the copolymer structured in the shape of micelles (20 nm diameter) and very small domains with 50–200 nm diameter, whereas unmodified PPE formed much larger domains (1.5 μm) containing copolymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3985–3991, 2008     

Synthesis and solvent‐dependent micellization of the amphiphilic block copolymer poly(styreneboronic acid)‐block‐polystyrene

The amphiphilic organoboron block copolymer poly (styreneboronic acid)‐block‐polystyrene ( PSBA‐b‐PS ) has been prepared through a postpolymerization modification route from the silicon‐functionalized block copolymer poly(4‐trimethylsilylstyrene)‐block‐polystyrene ( PSSi‐b‐PS ). PSBA‐b‐PS is obtained through highly selective reaction of PSSi‐b‐PS with BBr₃ at room temperature and subsequent hydrolysis of the BBr₂‐functionalized intermediate. Transmission electron microscopy studies demonstrate that PSBA‐b‐PS undergoes pH dependent micellization in aqueous solution. Different morphologies could be realized by using different mixtures of water and organic solvents. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2438–2445, 2010     

Self‐organization and luminescent properties of nanostructured europium (III)–block copolymer complex thin films

We introduce a simple method to create nanosized, ordered, and highly luminescent thin film of Eu (III)–block copolymer complex. Micelles of polystyrene–block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) in P4VP‐selective solvents (ethanol/N,N‐dimethylformamide (DMF) mixture) serve as nanoreactors for the synthesis of Eu(III)–block copolymer complex with the presence of 1,10‐phenanthroline (Phen) as cooperative ligand. The resulted quaternary complexes were characterized by FT‐IR spectra, ¹⁵N NMR spectra, and elemental analysis, indicative of a composition of Eu(III)–(PS‐b‐P4VP)–Phen–5DMF. Atomic force microscopy and transmission electron microscopy investigations reveal that the Eu(III)–(PS‐b‐P4VP)–Phen–5DMF complex can self‐organize into hexagonally ordered thin films when dip‐coated from the solution onto silicon or silica glass substrates. Such ordered thin films can emit red fluorescence of Eu³⁺ with strong intensity and long lifetime. This method can be easily extended to prepare other ordered luminescent rare earth–polymer complexes thin films. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2181–2189, 2005     

Block copolymer containing poly(3‐hexylthiophene) and poly(4‐vinylpyridine): Synthesis and its interaction with CdSe quantum dots for hybrid organic applications

Poly(3‐hexylthiophene)‐b‐poly(4‐vinylpyridine) diblock copolymer was synthesized by RAFT polymerization of 4‐vinyl pyridine using a trithiocarbonate‐terminated poly(3‐hexylthiophene) macro‐RAFT agent. The optoelectronic properties and the morphology of the block copolymer blends with CdSe quantum dots were investigated. UV‐vis and fluorescence experiments were performed to prove the charge transfer between CdSe and poly(3‐hexylthiophene)‐b‐poly(4‐vinylpyridine) diblock copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Poly(methyl silsesquioxane)/amphiphilic block copolymer hybrids and their porous derivatives: Poly(styrene‐block‐acrylic acid) and poly(styrene‐block‐3‐trimethoxysilylpropyl methacrylate)

Porous poly(methyl silsesquioxane) (PMSSQ) films were prepared from PMSSQ/amphiphilic block copolymer (ABC) hybrids, and this was followed by spin coating and multistep baking. The ABCs were poly(styrene‐block‐acrylic acid) (PS‐b‐PAA) and poly(styrene‐block‐3‐trimethoxysilylpropyl methacrylate) (PS‐b‐PMSMA), which were synthesized by living polymerization. The chemical bonding between the ABCs and PMSSQ resulted in significant differences in the morphologies and properties of the hybrids and their porous derivatives. Both intramolecular and intermolecular hydrogen bonding existed in the PMSSQ/PS‐b‐PAA hybrid and led to macrophase separation. Through the modification of the chemical structure from the poly(acrylic acid) segment to PMSMA, covalent bonding between PMSSQ and PMSMA occurred and prevented the macrophase separation and initial pyrolysis of the ABC. Modulated differential scanning calorimetry results also suggested a significant difference in the miscibility of the two hybrid systems. The chemical bonding resulted in higher retardation of the symmetry‐to‐nonsymmetry Si? O? Si structural transformation for PMSSQ/PS‐b‐PMSMA than for PMSSQ/PS‐b‐PAA according to Fourier transform infrared studies. The pore size of the nanoporous thin film from the PMSSQ/PS‐b‐PMSMA hybrid was estimated by transmission electron microscopy to be less than 15 nm. The refractive index and dielectric constant of the prepared porous films decreased from 1.354 to 1.226 and from 2.603 to 1.843 as the PS‐b‐PMSMA loading increased from 0 to 50 wt %, respectively. This study suggests that chemical bonding in hybrid materials plays a significant role in the preparation of low‐dielectric‐constant nanoporous films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4466–4477, 2004     

Effect of polystyrene‐b‐poly(ethylene oxide) on self‐assembly of polystyrene‐b‐poly(N‐isopropylacrylamide) in aqueous solution

Mixed micelles of polystyrene‐b‐poly(N‐isopropylacrylamide) (PS‐b‐PNIPAM) and two polystyrene‐b‐poly(ethylene oxide) diblock copolymers (PS‐b‐PEO) with different chain lengths of polystyrene in aqueous solution were prepared by adding the tetrahydrofuran solutions dropwise into an excess of water. The formation and stabilization of the resultant mixed micelles were characterized by using a combination of static and dynamic light scattering. Increasing the initial concentration of PS‐b‐PEO in THF led to a decrease in the size and the weight average molar mass (〈M_w〉) of the mixed micelles when the initial concentration of PS‐b‐ PNIPAM was kept as 1 × 10^?3 g/mL. The PS‐b‐PEO with shorter PS block has a more pronounced effect on the change of the size and 〈M_w〉 than that with longer PS block. The number of PS‐b‐PNIPAM in each mixed micelle decreased with the addition of PS‐b‐PEO. The average hydrodynamic radius 〈R_h〉 and average radius of gyration 〈R_g〉 of pure PS‐b‐PNIPAM and mixed micelles gradually decreased with the increase in the temperature. Both the pure micelles and mixed micelles were stable in the temperature range of 18 °C–39 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1168–1174, 2010     

Synthesis and characterization of six‐arm star polystyrene‐block‐poly (3‐hexylthiophene) copolymer by combination of atom transfer radical polymerization and click reaction

A novel six‐arm star block copolymer comprising polystyrene (PS) linked to the center and π‐conjugated poly (3‐hexylthiophene) (P3HT) was successfully synthesized using a combination of atom transfer radical polymerization (ATRP) and click reaction. First, star‐shaped PS with six arms was prepared via ATRP of styrene with the discotic six‐functional initiator, 2,3,6,7,10,11‐hexakis(2‐bromoisobutyryloxy)triphenylene. Next, the terminal bromides of the star‐shaped PS were substituted with azide groups. Afterward, the six‐arm star block copolymer PS‐b‐P3HT was prepared using the click coupling reaction of azide‐terminated star‐shaped PS with alkynyl‐terminated P3HT. Various techniques including ¹H NMR, Fourier‐transform infrared and size‐exclusion chromatography were applied to characterize the chemical structures of the intermediates and the target block copolymers. Their thermal behaviors and optical properties were investigated using differential scanning calorimetry and UV–vis spectroscopy. Moreover, atomic force microscopy (AFM) was utilized to observe the morphology of the star block copolymer films. In comparison with two linear diblock copolymer counterparts, AFM results reveal the effect of the star block copolymer architecture on the microphase separation‐induced morphology in thin films. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Graftlike interpolymer complexes from poly(2‐vinylpyridine) and end‐sulfonic acid polystyrene and polyisoprene: Intermediates to noncovalently bonded block copolymer‐like micelles

The complexation between narrow molecular weight distribution poly(2‐vinylpyridine) (P2VP) and polystyrene (suPS) or polyisoprene (suPI) end‐functionalized with one sulfonic acid group was examined in tetrahydrofuran dilute solutions by a combination of static and dynamic laser light scattering. Both apparent weight‐average molecular weight (M_w,app) and hydrodynamic radius (R_h) of the complexes exhibited a maximum at a certain molar ratio of suPS chains to P2VP monomeric units. This indicated that the P2VP backbone may be saturated by the grafted end‐functionalized chains because of repulsion between the grafted chains. By changing the molar mass of P2VP from 100,000 to 30,000 g/mol, the values of M_w,app and R_h decreased. When suPI was used instead of suPS, similar trends were observed. In the latter case, it was possible to prepare block copolymer‐like micelles by transferring the P2VP/suPI blend solutions in decane, which is a selective solvent for PI. The non‐covalent‐bonded polymeric micelle characteristics were investigated as a function of sulfonic acid/2‐vinylpyridine units ratio as well as temperature. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2454–2461, 2003