Preparation and characterization of poly(2‐methacryloyloxyethyl phosphorylcholine)‐block‐poly(D,L‐lactide) polymer nanoparticles

A poly(D,L ‐lactide)–bromine macroinitiator was synthesized for use in the preparation of a novel biocompatible polymer. This amphiphilic diblock copolymer consisted of biodegradable poly(D,L ‐lactide) and 2‐methacryloyloxyethyl phosphorylcholine and was formed by atom transfer radical polymerization. Polymeric nanoparticles were prepared by a dialysis process in a select solvent. The shape and structure of the polymeric nanoparticles were determined by ¹H NMR, atomic force microscopy, and ζ‐potential measurements. The results of cytotoxicity tests showed the good cytocompatibility of the lipid‐like diblock copolymer poly(2‐methacryloyloxyethyl phosphorylcholine)‐block‐poly(D,L ‐lactide). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 688–698, 2007     

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     

Removal of poly(methyl methacrylate) in diblock copolymers films studied by grazing incidence small‐angle X‐ray scattering

Self‐assembly of diblock copolymers (BCP) into periodic arrays is a promising route to generate templates for the fabrication of nanoscopic elements, when one block is selectively removed. In cylindrical morphology polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) copolymer (BCP) films, the efficiency of different processes for removing the PMMA from cylinders is studied using grazing incidence small angle X‐ray scattering (GISAXS), x‐ray reflectivity and critical dimension scanning electron microscopy. The detailed analysis of the GISAXS patterns leads to the determination of the depth of cylindrical holes left by removal of the PMMA. It is found that the combination of a preliminary UV exposure followed by a wet treatment allows to remove totally the PMMA blocks. Furthermore, the optimization of both UV exposition time and solvent allows to preserve the PS matrix and interestingly for nanolithographic applications to decrease the process costs. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1137–1144     

Multiple morphologies of the aggregates from self‐assembly of diblock copolymer with relatively long corona‐forming block in dilute aqueous solution

Reported here is self‐assembly behavior in selective solvent of diblock copolymers with relatively long corona‐forming block compared to core‐forming block. Three diblock copolymers, poly(ethylene glycol) monomethyl ether‐b‐poly(methacryloyl‐L ‐leucine methyl ester), also denoted as MPEG‐b‐PMALM copolymer, were prepared by fixing MPEG block with an average number of repeating units of 115, whereas varying PMALM block with an average number of repeating unit of 44, 23, 9, respectively. Multiple morphologies, such as sphere, cylinder, vesicle, and their coexisted structures from self‐assembly of these diblock copolymers in aqueous media by changing block nonselective solvent and initial polymer concentration used in preparation, were demonstrated directly via TEM observation. These results herein might, therefore, demonstrate as an example that a wide range of morphologies can be accessed not only from “crew‐cut micelles” but also from “star‐micelles” by controlling over preparation strategies. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 364–371, 2010     

Biocompatible poly(ethylene glycol)‐poly(γ‐cholesterol‐L‐glutamate) copolymers: Synthesis,characterization, and in vitro studies

A novel amphiphilic poly(ethylene glycol)‐block‐poly(γ‐cholesterol‐L ‐glutamate) (mPEG–PCHLG) diblock copolymer has been synthesized. The mPEG–PCHLG copolymer has good biocompatibility and low toxicity. The mPEG–PCHLG copolymers could aggregate into nanoparticles with PCHLG blocks as the hydrophobic core and PEG blocks as the hydrophilic shell through emulsion solvent evaporation method. The copolymers were characterized by nuclear magnetic resonance spectroscopy, mass spectrum, Fourier transform infrared spectroscopy, and gel permeation chromatography. The particle sizes, size distributions, and zeta potentials of nanoparticles can also be determined by dynamic light scattering and transmission electron microscopy. This work provides a new and facile approach to prepare amphiphilic block copolymer nanoparticles with controllable performances. This novel copolymer may have potential applications in drug delivery and bioimaging applications.© 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

In situ synthesis of nano‐assemblies of the high molecular weight ferrocene‐containing block copolymer via dispersion RAFT polymerization

The in situ synthesis of the nano‐assemblies of the high molecular weight ferrocene‐containing block copolymer of poly(ethylene glycol)‐block‐poly(4‐vinylbenzyl ferrocenecarboxylate) (PEG‐b‐PVFC) via dispersion reversible addition‐fragmentation chain transfer (RAFT) polymerization was discussed. Taking the advantage of the accelerated polymerization rate of the dispersion RAFT polymerization, the nano‐objects of the well‐defined PEG‐b‐PVFC diblock copolymer with the polymerization degree (DP) of the ferrocene‐containing PVFC block up to 300 were prepared. It was found that the morphology of the PEG‐b‐PVFC diblock copolymer nano‐assemblies was dependent on the DP of the PEG and PVFC blocks, and nanospheres favorably formed in the case of the long PEG block and vesicles containing a thick and porous membrane were formed in the case of the short PEG block and long PVFC block, respectively. Our results demonstrate that the dispersion RAFT polymerization is an effective way to prepare the high molecular weight ferrocene‐containing block copolymer with interesting morphologies. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 900–909     

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     

Radical‐cured block copolymer‐modified thermosets

Poly(ethylene‐alt‐propylene)‐b‐poly(ethylene oxide) (PEP‐PEO) diblock copolymers were synthesized and added at 4 wt % to 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloxypropoxy)phenyl]propane (BisGMA), a monomer that cures using free radical chemistry. In separate experiments, poly(ethylene glycol) dimethacrylate (PEGDMA) was combined as a secondary monomer with BisGMA and the monomers were loaded with 4 wt % PEP‐PEO. The diblock copolymers self‐assembled into well‐dispersed spherical micelles with PEP cores and PEO coronas. No appreciable change in the final extent of cure of the thermosets was caused by the addition of diblock copolymer, except in the case of BisGMA, where the addition of the block copolymer increased extent of cure by 12%. Furthermore, the extent of cure was increased by 29% and 37% with the addition of 25 and 50 wt % PEGDMA, respectively. Elastic modulus and fracture resistance were also determined, and the values indicate that the addition of block copolymers does not significantly toughen the thermoset materials. This finding is surprising when compared with the large increase in fracture resistance seen in block copolymer‐modified epoxies, and an explanation is proposed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Synthesis of star‐shaped poly(D,L‐lactic acid‐alt‐glycolic acid)‐b‐poly(L‐lactic acid) with the poly(D,L‐lactic acid‐alt‐glycolic acid) macroinitiator and stannous octoate catalyst

Two types of three‐arm and four‐arm, star‐shaped poly(D,L ‐lactic acid‐alt‐glycolic acid)‐b‐poly(L ‐lactic acid) (D,L ‐PLGA50‐b‐PLLA) were successfully synthesized via the sequential ring‐opening polymerization of D,L ‐3‐methylglycolide (MG) and L ‐lactide (L ‐LA) with a multifunctional initiator, such as trimethylolpropane and pentaerythritol, and stannous octoate (SnOct₂) as a catalyst. Star‐shaped, hydroxy‐terminated poly(D,L ‐lactic acid‐alt‐glycolic acid) (D,L ‐PLGA50) obtained from the polymerization of MG was used as a macroinitiator to initiate the block polymerization of L ‐LA with the SnOct₂ catalyst in bulk at 130 °C. For the polymerization of L ‐LA with the three‐arm, star‐shaped D,L ‐PLGA50 macroinitiator (number‐average molecular weight = 6800) and the SnOct₂ catalyst, the molecular weight of the resulting D,L ‐PLGA50‐b‐PLLA polymer linearly increased from 12,600 to 27,400 with the increasing molar ratio (1:1 to 3:1) of L ‐LA to MG, and the molecular weight distribution was rather narrow (weight‐average molecular weight/number‐average molecular weight = 1.09–1.15). The ¹H NMR spectrum of the D,L ‐PLGA50‐b‐PLLA block copolymer showed that the molecular weight and unit composition of the block copolymer were controlled by the molar ratio of L ‐LA to the macroinitiator. The ¹³C NMR spectrum of the block copolymer clearly showed its diblock structures, that is, D,L ‐PLGA50 as the first block and poly(L ‐lactic acid) as the second block. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 409–415, 2002     

Crystallization‐dominated and microphase separation/crystallization‐coexisted structure of all‐conjugated phenylene–thiophene diblock copolymers

The crystallization‐dominated and microphase separation/crystallization‐coexisted structure of the all‐conjugated diblock copolymers poly(2,5‐dihexyloxy‐p‐phenylene)‐block‐(3‐hexylthiophene) (PPP‐b‐P3HT, denoted as BmTn) with different block compositions was affected by the aggregation state of the diblock copolymers in solvents with different solubilities. For B34T66, B62T38, and B75T25, the coexistence of microphase separation and crystallization was obtained in good solvent with few crystalline aggregates. For B34T66 with a longer P3HT block, densely stacked fiber crystal structures in thin films were found by using marginal solvents with crystalline aggregations in solutions. As for B62T38 and B75T25 with shorter P3HT block and longer PPP block, crystal structures were obtained by the use of solvents with a much larger solubility difference of the two blocks. Thus, microphase‐separated structures are prone to form from solutions with coil conformation and fiber crystals from solutions with larger aggregates, which resulted in the increased crystallinity. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1718–1726     

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     

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     

Radiation‐induced fabrication of polymer nanoporous materials from microphase‐separated structure of diblock copolymers as a template

Polymer nanoporous materials with periodic cylindrical holes were fabricated from microphase‐separated structure of diblock copolymers consisting of a radiation‐crosslinking polymer and a radiation‐degrading polymer through simultaneous crosslinking and degradation by γ‐irradiation. A polybutadiene‐block‐poly(methyl methacrylate) (PB‐b‐PMMA) diblock copolymer film that self‐assembles into hexagonally packed poly(methyl methacrylate) cylinders in polybutadiene matrix was irradiated with γ‐rays. Solubility test, IR spectroscopy, and TEM and SEM observations for this copolymer film in comparison with a polystyrene‐block‐poly(methyl methacrylate) diblock copolymer film revealed that poly(methyl methacrylate) domains were removed by γ‐irradiation and succeeding solvent washing to form cylindrical holes within polybutadiene matrix, which was rigidified by radiation crosslinking. Thus, it was demonstrated that nanoporous materials can be prepared by γ‐irradiation, maintaining the original structure of PB‐b‐PMMA diblock copolymer film. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5916–5922, 2007     

Facile preparation of core‐crosslinked micelles from azide‐containing thermoresponsive double hydrophilic diblock copolymer via click chemistry

Double hydrophilic diblock copolymer, poly(N,N‐dimethylacrylamide)‐b‐poly(N‐isopropylacrylamide‐co‐3‐azidopropylacrylamide) (PDMA‐b‐P(NIPAM‐co‐AzPAM), containing azide moieties in one of the blocks was synthesized via consecutive reversible addition‐fragmentation chain transfer polymerization. The obtained diblock copolymer molecularly dissolves in aqueous solution at room temperature, and can further supramolecularly self‐assemble into core‐shell nanoparticles consisting of thermoresponsive P(NIPAM‐co‐AzPAM) cores and water‐soluble PDMA coronas above the lower critical solution temperature of P(NIPAM‐co‐AzPAM) block. As the micelle cores contain reactive azide residues, core crosslinking can be facilely achieved upon addition of difunctional propargyl ether via click chemistry. In an alternate approach in which the PDMA‐b‐P(NIPAM‐co‐AzPAM) diblock copolymer was dissolved in a common organic solvent (DMF), the core‐crosslinked (CCL) micelles can be fabricated via “click” crosslinking upon addition of propargyl ether and subsequent dialysis against water. CCL micelles prepared by the latter approach typically possess larger sizes and broader size distributions, compared with that obtained by the former one. In both cases, the obtained (CCL) micelles possess thermoresponsive cores, and the swelling/shrinking of which can be finely tuned with temperature, rendering them as excellent candidates as intelligent drug nanocarriers. Because of the high efficiency and quite mild conditions of click reactions, we expect that this strategy can be generalized for the structural fixation of other self‐assembled nanostructures. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 860–871, 2008     

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     

Microdomain morphology of lamella‐forming diblock copolymer confined in a thin film

We report the self‐consistent field theory (SCFT) of the morphology of lamella‐forming diblock copolymer thin films confined in two horizontal symmetrical/asymmetrical surfaces. The morphological dependences of thin films on the polymer‐surface interactions and confinement, such as film thickness and confinement spatial structure, have been systematically investigated. Mechanisms of the morphological transitions can be understood mainly through the polymer‐surface interactions and confinement entropy, in which the plat confinement surface provides a surface‐induced effect. The confinement is expressed in the form of the ratio D/L₀, here D is film thickness, and L₀ is the period of bulk lamellar‐structure. Much richer morphologies and multiple surface‐induced morphological transitions for the lamella‐forming diblock copolymer thin films are observed, which have not been reported before. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1–10, 2009     

Degradation behaviors of monomethoxy poly(ethylene glycol)‐b‐poly(ε‐caprolactone) nanoparticles in aqueous solution

Monomethoxy poly(ethylene glycol)‐b‐poly(ε‐caprolactone)(MPEG‐b‐PCL) diblock copolymers were synthesized via a ring‐opening polymerization. The polymeric nanoparticles prepared by precipitation/solvent evaporation exhibit a core–shell structure, characterized by dynamic light scattering (DLS), nuclear magnetic resonance (NMR), and atomic force microscopy (AFM). The hydrolytic degradation of those nanoparticles was studied by DLS, NMR, and gel permeation chromatography (GPC). It was found that the molecular weight of PCL block in a copolymer significantly affects the stability of nanoparticles in aqueous solution and nanoparticles with shorter PCL block length degraded faster. The degradation behaviors could be divided into two stages with slow degradation at the interface region via swelling effect and fast degradation at inner core via caves and channels formed by cleavage of ester bonds. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis,morphology, and field‐effect transistor characteristics of new crystalline–crystalline diblock copolymers of poly(3‐hexylthiophene‐block‐steryl acrylate)

We report the synthesis, morphology, and charge‐transporting characteristics of new crystalline–crystalline diblock copolymers, poly(3‐hexylthiophene‐block‐stearyl acrylate) (P3HT‐b‐PSA). Three different diblock copolymers, P1 , P2 , and P3 , with P3HT/PSA polymerization degree block ratios of 60/26, 60/50, and 60/360, respectively, were prepared for investigating the morphology‐property relationship and the dependence of optoelectronic properties on the block copolymer structure. Small‐ and wide‐angle X‐ray scattering indicated the presence of both P3HT and PSA crystalline domains and the presence of microphase separation among blocks. The transmission electron microscopy and atomic force microscopy results revealed that the diblock copolymers cast from chlorobenzene, tended to form needle‐like morphologies. The field‐effect mobilities of the diblock copolymers deposited on untreated SiO₂ substrates, decreased with increasing PSA block length. In a sharp contrast, the mobilities enhanced with increasing PSA content when the P3HT‐b‐PSA was deposited on phenyltrichlorosilane (PTS)‐treated substrates. The copolymers with a 60/360 P3HT/PSA ratio showed a good mobility of 4 × 10^?3 cm² V^?1 s^?1 and a high on/off ratio of 7 × 10⁶ on PTS‐treated substrates. This study highlighted the importance of the block ratio, the substrate and self‐assembly structures on the charge transport characteristics of the crystalline–crystalline conjugated diblock copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Poly(ϵ‐caprolactone‐b‐glycolide) and poly(D,L‐lactide‐b‐glycolide) diblock copolyesters: Controlled synthesis,characterization, and colloidal dispersions

Living ω‐aluminum alkoxide poly‐ϵ‐caprolactone and poly‐D,L ‐lactide chains were synthesized by the ring‐opening polymerization of ϵ‐caprolactone (ϵ‐CL) and D,L ‐lactide (D,L ‐LA), respectively, and were used as macroinitiators for glycolide (GA) polymerization in tetrahydrofuran at 40 °C. The P(CL‐b‐GA) and P(LA‐b‐GA) diblock copolymers that formed were fractionated by the use of a selective solvent for each block and were characterized by ¹H NMR spectroscopy and differential scanning calorimetry analysis. The livingness of the operative coordination–insertion mechanism is responsible for the control of the copolyester composition, the length of the blocks, and, ultimately, the thermal behavior. Because of the inherent insolubility of the polyglycolide blocks, microphase separation occurs during the course of the sequential polymerization, resulting in a stable, colloidal, nonaqueous copolymer dispersion, as confirmed by photon correlation spectroscopy. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 294–306, 2001     

Insights into poly(3‐hexylthiophene)‐b‐poly(ethylene oxide) block copolymer: Synthesis and solvent‐induced structure formation in thin films

We report the synthesis, characterization, and solvent‐induced structure formation in thin films of an amphiphilic rod‐coil conjugated block copolymer, poly(3‐hexylthiophene)‐b‐poly(ethylene oxide). The diblock copolymers were prepared by a facile click reaction and their characterizations as well as thermal, crystalline, optical properties, and self‐assembly behavior have been investigated in detail. A series of morphologies including two‐phase separated nanostructure, nanofibrils, and their mixed morphology could be obtained depending on the selectivity of solvents to different blocks. Structural analyses demonstrate there is a subtle balance between microphase separation of copolymer and the π‐π stacking of the conjugated P3HT and such balance can be controlled by changing the solvents of different selectivity in solution and the length of P3HT block. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012