Alignment and orientational proliferation of HEX cylinders in a polystyrene-block-polyisoprene-block-polystyrene copolymer in the presence of clay

We investigated the effect of an anisotropic silicate layer on the alignment and orientational proliferation of hexagonally packed cylinder microdomains of a block copolymer in the presence of a clay by using synchrotron small angle X-ray scattering (SAXS), rheology, and transmission electron microscopy (TEM). The block copolymer employed in this study was polystyrene-block-polyisoprene-block-polystyrene copolymer (SIS). The degree of intercalation of the clay in the presence of SIS was examined by wide angle X-ray diffraction (WAXD).Almost all of the HEX cylinders in neat SIS are aligned toward the flow direction after large amplitude oscillatory shearing is applied to the specimens. However, some tactoids in nanocomposites are not aligned, although most tactoids are also aligned to the flow direction. Due to HEX cylinders near tactoids, which are not aligned to the flow direction, the orientational factor of HEX cylinders in SIS/clay nanocomposites is smaller than that of neat SIS. However, once HEX cylinders in SIS/clay nanocomposites are degenerated after experiencing body-centered cubic microdomains, the decrease in the orientational factor from original aligned HEX is smaller compared with neat SIS.     

Nanostructured polymer blends based on polystyrene‐b‐polybutadiene‐b‐poly(methyl methacrylate) triblock copolymers modified with polystyrene and/or poly(methyl methacrylate) homopolymers

Morphologies of polymer blends based on polystyrene‐b‐ polybutadiene‐b ‐poly(methyl methacrylate) (SBM) triblock copolymer were predicted, adopting the phase diagram proposed by Stadler and co‐workers for neat SBM block copolymer, and were experimentally proved using atomic force microscopy. All investigated polymer blends based on SBM triblock copolymer modified with polystyrene (PS) and/or poly(methyl methacrylate) (PMMA) homopolymers showed the expected nanostructures. For polymer blends of symmetric SBM‐1 triblock copolymer with PS homopolymer, the cylinders in cylinders core?shell morphology and the perforated lamellae morphology were obtained. Moreover, modifying the same SBM‐1 triblock copolymer with both PS and PMMA homopolymers the cylinders at cylinders morphology was reached. The predictions for morphologies of blends based on asymmetric SBM‐2 triblock copolymer were also confirmed experimentally, visualizing a spheres over spheres structure. This work presents an easy way of using PS and/or PMMA homopolymers for preparing nanostructured polymer blends based on SBM triblock copolymers with desired morphologies, similar to those of neat SBM block copolymers. © 2017 Society of Chemical Industry     

Flexible and flame‐retardant S‐SEB‐S triblock copolymer/PPE nano‐alloy

We observed that modified polyphenylene ether (PPE) was solubilized in thermoplastic styrenic elastomer (TPS) and that a two‐phase lacy structure formed on nanometer scales when the TPS composition was 67 wt % and modified PPE and polystyrene‐block‐poly(styrene‐co‐ethylene‐co‐butylene)‐block‐polystyrene (S‐SEB‐S triblock copolymer) were blended. However, the molecular weight of the outer PS block segments M_outPS and the content of the outer PS block segments ?_outPS were <10,000 g/mol and 20 wt %, respectively. The resulting S‐SEB‐S/modified PPE nano‐alloy exhibited both flexibility and flame retardancy, unlike other materials, where a trade‐off exists between these two properties; that is, the flame retardancy was excellent when the phosphorus additive was present. This combination of properties might be attributed to the two‐phase nanometer‐scale structure consisting of flame‐retardant styrene/PPE domains and a continuous soft, lacy SEB matrix. The results for polystyrene‐block‐poly(ethylene‐co‐butylene)‐block‐polystyrene (S‐EB‐S triblock copolymer)/modified PPE blends were presented for comparison. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40446.     

Toughening of epoxy thermosets with polystyrene‐block‐polybutadiene‐block‐ polystyrene triblock copolymer via formation of nanostructures

In this contribution, we reported to utilize polystyrene‐block‐polybutadiene‐block‐polystyrene (PS‐b‐PB‐b‐PS), a commercial triblock copolymer to toughen epoxy thermosets. First, a PS‐b‐PB‐b‐PS triblock copolymer was chemically modified with hydroboration‐oxidation reaction, with which the midblock was hydroxylated whereas the endblocks remained unaffected. It was found that the degree of hydroxylation was well controlled. One of the hydroxylated PS‐b‐PB‐b‐PS samples was then used as the macromolecular initiator to synthesize a poly(ε‐caprolactone)‐grafted PS‐b‐PB‐b‐PS via the ring‐opening polymerization. It was found that the PS‐b‐PB‐b‐PS with poly(ε‐caprolactone) grafts can be successfully employed to nanostructure epoxy thermosets; the “core‐shell” microdomains composed of PB and PS were generated in the nanostructured thermosets. The nanostructured thermosets displayed improved fracture toughness. POLYM. ENG. SCI., 59:2387–2396, 2019. © 2019 Society of Plastics Engineers     

Plasticization of nano‐CaCO3 in polystyrene/nano‐CaCO3 composites

The shear rheological properties of polystyrene (PS)/nano‐CaCO₃ composites were studied to determine the plasticization of nano‐CaCO₃ to PS. The composites were prepared by melt extrusion. A poly(styrene–butadiene–styrene) triblock copolymer (SBS), a poly(styrene–isoprene–styrene) triblock copolymer (SIS), SBS‐grafted maleic anhydride (SBS–MAH), and SIS‐grafted maleic anhydride were used as modifiers or compatibilizers. Because of the weak interaction between CaCO₃ and the PS matrix, the composites with 1 and 3 phr CaCO₃ loadings exhibited apparently higher melt shear rates under the same shear stress with respect to the matrix polymer. The storage moduli for the composites increased with low CaCO₃ concentrations. The results showed that CaCO₃ had some effects on the compatibility of PS/SBS (or SBS–MAH)/CaCO₃ composites, in which SBS could effectively retard the movement of PS chain segments. The improvement of compatibility, due to the chemical interaction between CaCO₃ and the grafted maleic anhydride, had obvious effects on the rheological behavior of the composites, the melt shear rate of the composites decreased greatly, and the results showed that nano‐CaCO₃ could plasticize the PS matrix to some extent. Rheological methods provided an indirect but useful characterization of the composite structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Organic/inorganic nanoobjects with controlled shapes from gelable triblock copolymers

A functional gelable triblock copolymer, poly(2-vinylpyridine)-block-poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene (P2VP-b-PTEPM-b-PS), was prepared by the combination of reversible addition-fragmentation chain transfer (RAFT) mediated radical polymerization and copper catalyzed click chemistry. Bulk microphase separation of P2VP₃₁₀-b-PTEPM₅₈-b-PS₃₂₂ under different conditions was studied in order to prepare organic/inorganic nanoobjects by a procedure of crosslinking PTEPM phases and dispersing in a solvent. The conditions included using different annealing solvents and adding stearic acids to form supramolecular complexes with P2VP blocks respectively. Then the packed cylinders with P2VP cores and PTEPM shells dispersed in the PS matrix, lamella with alternating PS, PTEPM and P2VP layers, and the inverse cylindrical morphology with PS cores and PTEPM shells dispersed in the matrix of P2VP/stearic acid complex were obtained respectively just from the same triblock copolymer sample. After crosslinking PTEPM microdomains by sol-gel process and dispersing in solvents, a series of organic/inorganic polymeric nanoobjects, including two types of nanofibers with inverse internal structure and one novel kind of nanoplates, were produced. Further modification of the fibers with P2VP cores has been studied.     

Toughening of immiscible PPE/SAN blends by triblock terpolymers

The mechanical performance of immiscible blends of poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and poly(styrene-co-acrylonitrile) (SAN) and the subsequent influence of compatibilisation by tailored polystyrene-block-polybutadiene-block-poly(methyl methacrylate) triblock terpolymers (SBM) on the mechanical performance under static and dynamic loads is analysed in detail. A PPE/SAN 60/40 blend was selected as a base system for the compatibilisation experiments. The observed static tensile behaviour is described by micromechanical models and correlated to the blend microstructures as observed by transmission electron microscopy. In most cases, the addition of the SBM triblock terpolymers further enhances the ductility of the blend while only leading to a minor reduction of modulus and strength. Triblock terpolymers with symmetric end blocks, mainly located at the interface between PPE and SAN, led to nearly isotropic specimens. In contrast, SBM materials with a longer polystyrene block predominantly formed micelles in the PPE phase and the blends revealed a highly anisotropic morphology. Comparative investigations of the fatigue crack growth behaviour parallel to the direction of injection also reflected this variation in mechanical anisotropy of the compatibilised blends. A poor toughness and a predominant interfacial failure were observed in the case of the SBM with a long polystyrene block. In contrast, a considerable improvement in properties as a result of pronounced plastic deformations was observed for blends compatibilised by triblock terpolymers with symmetric end blocks. The systematic correlation between morphology and mechanical performance of compatibilised PPE/SAN blends established in this study provides an efficient way for the desired selection of suitable and effective compatibilising agents, ensuring both a superior multiaxial toughness as well as a high strength and modulus of the overall system.     

Suspension polymerization stabilized by triblock copolymer with CdS nanoparticles

In this paper, a new method to prepare polymer colloid particles stabilized by triblock copolymer with CdS nanoparticles was described. Poly(ethylene glycol-block-styrene-block-2-(dimethylamino) ethyl methacrylate) (PEG-b-PS-b-PDMAEMA) triblock copolymer was synthesized by sequential ATRP method. Micelles with CdS nanoparticles in the corona were prepared by “in situ” reaction of hydrogen sulfide with cadmium ion clusters in the corona of the micelles. The size of the CdS nanoparticles is affected by molar ratio of DMAEMA to cadmium ions and polymer concentration in the solution. When introduced into o/w emulsion the micelles reassemble on the surface of styrene oil droplets. PS colloid particles stabilized by triblock copolymer with CdS nanoparticles were achieved by suspension polymerization. TEM image indicates that CdS nanoparticles locate at the surface of the PS colloid particles.     

Viscoelastic and photo-actuation studies of composites based on polystyrene-grafted carbon nanotubes and styrene-b-isoprene-b-styrene block copolymer

Photoactuating composites based on the linear triblock copolymer polystyrene-b-polyisoprene-b-polystyrene (SIS) were prepared by incorporation of polystyrene-modified multiwalled carbon nanotubes (MWCNT–PS). Modification of MWCNT was performed by surface-initiated atom transfer radical polymerization (SI ATRP) of styrene. The presence of the polystyrene chains on the MWCNT surface facilitated their dispersion in the SIS matrix. Improved interactions of the modified MWCNT–PS compared to neat MWCNT were confirmed by dynamic mechanical analysis. The activation energy of glass transition of the polystyrene phase in the MWCNT–PS/SIS composite increased significantly compared to the neat SIS matrix, while the incorporation of neat MWCNT to the SIS matrix disturbed the physical cross-linking of the SIS and degraded its elastic properties. The photo-actuation ability of the MWCNT–PS/SIS composite was proved using atomic force microscopy.     

Compatibility of polystyrene/polyolefin blends containing compatibilizing agents, 2. Extraction behavior

Polystyrene (PS)/polyolefin (PO) blends in various mixing ratios compatibilized by a triblock copolymer polystyrene‐block‐poly(ethene‐co‐butylene)‐block‐polystyrene (SEBS) and a diblock copolymer polystyrene‐block‐poly(ethene‐co‐propene) (SEP) and subsequently γ‐irradiated were prepared. The blends have been subjected to extraction in different solvents (chloroform or toluene) for various periods of time to obtain porous films. The efficiency of the extraction and the morphology of the films have been assessed by infrared spectrometry (IR), optical and electronic microscopy, differential scanning calorimetry (DSC) and thermogravimetry (TG); glass transition, melting heat, thermal stability, overall kinetic parameters and weight losses have been evaluated. The extraction behavior is close related to compatibility of the components, so on the base of the obtained results optima compatibility ratios have been established.     

Effects of sample preparation and flow geometry on the rheological behaviour and morphology of microphase-separated block copolymers: comparison of cone-and-plate and capillary data

The steady shear viscosities of two microphase-separated triblock copolymers, a polystyrene-block-polybutadiene-block-polystyrene copolymer (Kraton 1102) and a polystyrene-block-polyisoprene-block-polystyrene copolymer (Kraton 1107), were measured at various temperatures, using a cone-and-plate rheometer at low shear rates (ca. 0.01–10s⁻¹) and a capillary rheometer at high shear rates (ca. 5–5000 s⁻¹). In order to investigate the effect of sample preparation on the viscosity, specimens of Kraton 1102 were prepared using two different methods: (a) solvent film casting and (b) compression moulding. Samples of Kraton 1107 were prepared only by compression moulding. In the present study we found that (a) for compression-moulded specimens the shear viscosities obtained using a cone-and-plate rheometer did not overlap those obtained using a capillary rheometer, while for solvent-cast specimens there was a reasonably good agreement between the two, and (b) the viscosities of solvent-cast specimens were much lower than those of compression-moulded specimens. This observation was explained with the aid of transmission electron micrographs, which were taken of ultrathin sections cut parallel and perpendicular to the direction of shear. We found from transmission electron micrographs that the application of steady shear flow affected greatly the morphology of Kraton 1102 having cylindrical microdomains of polystyrene phase, whereas it affected little the morphology of Kraton 1107 having spherical microdomains of polystyrene phase. Also measured were the complex shear viscosities of the two block copolymers at various temperatures. We have shown that neither time-temperature superposition nor the Cox-Merz rule is applicable to microphase-separated block copolymers.     

Domain nucleation dictates overall nanostructure in composites of block copolymers and model nanorods

The detailed nanostructure of composites formed from block copolymers and nanoparticles is known to depend sensitively on the preferred morphology of the block copolymer, on the shapes of the particles, and on interactions between the two components. But it can also depend on the kinetics of self-assembly in the polymer, and there are circumstances under which the kinetics of morphologically selective domain nucleation and growth determine the overall nanostructure of the composite. To study the mechanism of morphological seeding in block-copolymer nanocomposites, we have combined cylinder phases of polystyrene-block-polyisoprene diblock (as a solution in dibutylphthalate) and poly(styrene-block-isoprene-block-styrene) triblock (as a blend with homopolystyrene) copolymers with gold nanorods of different diameters and surface treatments. Polarized optical microscopy and transmission electron microscopy on these composites demonstrate that the nanorods selectively nucleate coaxial domains of copolymer cylinders (i.e., domains of cylinders aligned along the same axis as the nanorod). These single nucleation events occur regardless of nanorod diameter and surface character, and determine the order of most of the surrounding polymer. Mesoscale modeling of the nucleation process, performed with nanorods of different diameters and with different polymer-surface interactions, illustrates the mechanism by which copolymer-dispersed nanorods with different sizes and surface chemistry can template the organization of cylindrical copolymer domains.     

Synthesis and morphological studies of polyisoprene-block-polystyrene-block-poly(vinyl methyl ether) triblock terpolymer

The triblock terpolymer (PI-b-PS-b-PVME) consisting of polyisoprene (PI), polystyrene (PS) and poly(vinyl methyl ether) (PVME) was synthesized by coupling reaction between living PI-b-PS anion and end-chlorinated PVME prepared via living cationic polymerization. This polymer is an amphiphilic block polymer and unique in a sense that it exhibits complex phase behavior because PS and PVME have a lower critical solution temperature (LCST)-type phase diagram while PI and PS (or PVME) have an UCST-type phase diagram. This unique architecture would result in a step-wise microphase separation to form a three-phase microdomain structure. It was observed by transmission electron microscopy with ultrathin sections that the toluene-cast film of PI-b-PS-b-PVME has a two-phase lamellar structure consisting of PI microdomains and mixed PS/PVME microdomains. Applying a drop of water onto the ultrathin sections induced further microphase separation between PS and PVME within the lamellar microdomains resulting in the three-phase structure. Water is a selective solvent for PVME and might have lowered the order-disorder temperature between PS and PVME. This step-wise microphase separation may be a new technique to control microphase-separated structures in triblock terpolymers.     

Nanophase morphology and crystallization in poly(vinylidene fluoride)/polydimethylsiloxane‐block‐poly(methyl methacrylate)‐block‐polystyrene blends

An approach to achieve confined crystallization of ferroelectric semicrystalline poly(vinylidene fluoride) (PVDF) was investigated. A novel polydimethylsiloxane‐block‐poly(methyl methacrylate)‐block‐polystyrene (PDMS‐b‐PMMA‐b‐PS) triblock copolymer was synthesized by the atom‐transfer radical polymerization method and blended with PVDF. Miscibility, crystallization and morphology of the PVDF/PDMS‐b‐PMMA‐b‐PS blends were studied within the whole range of concentration. In this A‐b‐B‐b‐C/D type of triblock copolymer/homopolymer system, crystallizable PVDF (D) and PMMA (B) middle block are miscible because of specific intermolecular interactions while A block (PDMS) and C block (PS) are immiscible with PVDF. Nanostructured morphology is formed via self‐assembly, displaying a variety of phase structures and semicrystalline morphologies. Crystallization at 145 °C reveals that both α and β crystalline phases of PVDF are present in PVDF/PDMS‐b‐PMMA‐b‐PS blends. Incorporation of the triblock copolymer decreases the degree of crystallization and enhances the proportion of β to α phase of semicrystalline PVDF. Introduction of PDMS‐b‐PMMA‐b‐PS triblock copolymer to PVDF makes the crystalline structures compact and confines the crystal size. Moreover, small‐angle X‐ray scattering results indicate that the immiscible PDMS as a soft block and PS as a hard block are localized in PVDF crystalline structures. © 2019 Society of Chemical Industry     

Crystallization behavior of dry‐brush PEO‐PS block copolymer and PEO homopolymer blend

The crystallization behavior of semicrystalline PEO homopolymer/triblock PS‐PEO‐PS copolymer blend system, which exhibited “Dry‐Brush” in the melt. A symmetric polystyrene–poly(ethylene oxide)–polystyrene triblock copolymer was blended with PEO homopolymer (h‐PEO) having the same molecular weight as that of the PEO block in the copolymer. Considering the composition of the blend (W_ps ≥ 0.8), PEO spheres were formed in the blend. Because of the dry‐brush phase behavior of this blend, h‐PEO added was localized in the PEO microdomains, which increases the domain size without changing the microdomain morphology. The crystallization of PEO block was confined within the microdomains and the crystallization temperature was about 60°C lower than normal. Self‐seeding tests were performed to clarify the nucleation mechanism of the blend. Because the droplets size varies greatly, multicrystallization peaks were witnessed in the self‐seeding process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Compatibilisation of PPE/SAN blends by triblock terpolymers: Correlation between block terpolymer composition, morphology and properties

Immiscible blends of poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and poly(styrene-co-acrylonitrile) (SAN) with a weight composition of 60/40 were compatibilised by polystyrene-block-polybutadiene-block-poly(methyl methacrylate) triblock terpolymers (SBM) using a two-stage melt-processing approach. In order to investigate the influence of the SBM composition on the compatibilisation efficiency, the block lengths of the triblock terpolymers were systematically varied. The resulting morphological features of the blend systems as function of SBM composition and processing parameters are correlated with the resulting thermal and thermo-mechanical properties. In the ideal case, SBM should be located at the interface as PS is miscible with PPE while PMMA is miscible with SAN. The elastomeric middle block as an immiscible component should remain at the interface. This particular morphological arrangement is known as the ‘raspberry morphology’. A detailed TEM analysis of the blend morphologies following initial extrusion-compounding revealed a high compatibilisation efficiency of the SBM types with equal lengths of the end blocks and, furthermore, the desired raspberry morphology was achieved. In contrast, high PS contents in comparison to the other blocks led to a pronounced micelle formation in the PPE phase. Further evaluation of the blend structures following injection-moulding indicated that the morphologies remain relatively stable during this second melt-processing step. A detailed thermal analysis of all blend systems supports the interpretation of the observed morphological features. The fundamental correlation between SBM composition and blend morphology established in this study opens the door for the controlled development of interfacial properties of such compatibilised PPE/SAN blends during melt-processing.     

Amphiphilic block copolymer poly(lactic acid)‐block‐(glycidylazide polymer)‐block‐polystyrene: synthesis and self‐assembly

The triblock energetic copolymer poly(lactic acid)‐block‐(glycidylazide polymer)‐block‐polystyrene (PLA‐b‐GAP‐b‐PS) was synthesized successfully through atom‐transfer radical polymerization (ATRP) of styrene and ring‐opening polymerization of d,l ‐lactide. The energetic macroinitiator GAP‐Br, which was made from reacting equimolar GAP with α‐bromoisobutyryl bromide, firstly triggered the ATRP of styrene with its bromide group, and then the hydroxyl group on the GAP end of the resulting diblock copolymer participated in the polymerization of lactide in the presence of stannous octoate. The triblock copolymer PLA‐b‐GAP‐b‐PS had a narrow distribution of molecular weight. In the copolymer, the PS block was solvophilic in toluene and improved the stability of the structure, the PLA block was solvophobic in toluene and served as the sacrificial component for the preparation of porous materials, and GAP was the basic and energetic material. The three blocks of the copolymer were fundamentally thermodynamically immiscible, which led to the self‐assembly of the block copolymer in solution. Further studies showed that the concentration and solubility of the copolymer and the polarity of the solvent affected the morphology and size of the micelles generated from the self‐assembly of PLA‐b‐GAP‐b‐PS. The micelles generated in organic solvents at 10 mg mL^?1 copolymer concentration were spherical but became irregular when water was used as a co‐solvent. The spherical micelles self‐assembled in toluene had three distinct layers, with the diameter of the micelles increasing from 60 to 250 nm as the concentration of the copolymer increased from 5 to 15 mg L^?1. © 2017 Society of Chemical Industry     

Deformation behavior of styrene-block-butadiene-block-styrene triblock copolymers having different morphologies

Deformation behavior of styrene-block-butadiene-block-styrene (SBS) triblock copolymers having different morphologies was investigated. Due to the combination of different methods which provide information on different deformation levels (macroscopic, microscopic and molecular) complex deformation mechanisms for each type of SBS block copolymer (including glassy-rubber alternating lamellae, rubber cylinders in glassy matrix and hard domains in soft matrix morphology) could be revealed. In combination with tensile tests, Fourier transform infrared (FTIR) spectroscopy was successfully applied to study the change of orientation in individual phases using the absorption bands at 1493 and 966 cm⁻¹ for polystyrene (PS) and polybutadiene (PB) phases, respectively. For all the block copolymers investigated the PB phase always oriented stronger than the PS phase because of its lower Young's modulus. However, differences in orientation in both phases were influenced by an appropriate stress distribution within the specimens during deformation, which, in fact, depends on the morphology of the polymers. Additionally, atomic force microscopy revealed local morphological changes during uniaxial stretching, which, in fact, depend on the arrangement of the structural units.     

Synthesis and characterization of (star polystyrene)-block-(polyisoprene)-block-(star polystyrene) copolymers

A (star polystyrene)-block-(linear polyisoprene)-block-(star polystyrene) copolymer, (S)_nI(S)_n, was prepared. The star polystyrene was produced via anionic polymerization of polystyrene macromonomers each containing an unsaturated double bond (vinyl) at the chain end. This vinyl-terminated polystyrene macromonomer (SSTM) was obtained beforehand via the synthesis of a living polystyrene using alkyllithium and the termination with p-chloromethylstyrene (PCMS). The living site in the core of the star polystyrene enabled the construction of the succeeding polyisoprene block resulting in the living (star polystyrene)-block-(linear polyisoprene) copolymer, (S)_nI. This living diblock copolymer was then coupled with 1,2-dibromoethane (DBE) to form the well-defined (S)_nI(S)_n. Compared to a linear polystyrene-block-polyisoprene-block-polystyrene, SIS, with the same molecular weight, (S)_nI(S)_n had a higher T_g and exhibited a lamellae-forming phase separation in conjunction with many dislocation defects. The thermal stability appeared independent of the molecular structure, and the radius of gyration and viscosity of (S)_nI(S)_n were much smaller than SIS.     

Crystallization behavior of “wet brush” and “dry brush” blends of PS‐b‐PEO‐b‐PS/h‐PEO

The crystallization behavior of the blending system consists of homopolymer poly(ethylene oxide) (h‐PEO) with different molecular weights, and polystyrene‐block‐poly (ethylene oxide)‐block‐polystyrene (PS‐b‐PEO‐b‐PS) triblock copolymer has been investigated by DSC measurements. The crystallization of PEO block (b‐PEO) in block copolymer occurs under much lower temperature than that of the h‐PEO in the bulk (ΔT > 65 °C), which is attributed to the homogeneous nucleation crystallization behavior of the b‐PEO microdomains. In both the “dry‐brush” and the “wet brush” blending systems, the homogeneous nucleation crystallization temperature of PS‐b‐PEO‐b‐PS/h‐PEO blends increases due to the increase of the domain size. The heterogeneous nucleation crystallization temperatures of h‐PEO in the wet brush blending systems are higher than that of the corresponding h‐PEO in the bulk. At the same time, the heterogeneous nucleation crystallization temperature of b‐PEO10000 decreases from 43°C to 30°C and 40°C in the h‐PEO600 and h‐PEO2000 blending systems, respectively, because of the stretching of the PEO chains in the wet brush. However, this kind of phenomenon does not happen in the dry brush blending systems. The self‐seeding procedure was used to further ascertain the nucleation mechanism in the crystallization process. As a result, the self‐seeding domains have been confirmed, and the difference between the dry brush and wet brush systems has been observed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009