Ionic conductivities of the complexes of LiClO4 and alternating copolymers of oligomeric poly(ethylene oxide) having biphenyl units in the backbone

A series of copolymers of predominantly poly(ethylene oxide) (PEO) with biphenyl (BP) units in the backbone were synthesized. The solid polymer electrolytes (SPEs) were prepared from these copolymers (BP-PEG) employing lithium perchlolate (LiClO₄) as a lithium salt and their ionic conductivities were investigated to exploit the structure–ionic conductivity relationships as a function of chain length ratio between the flexible PEO chains and rigid BP units. The ionic conductivity increases with increasing PEO length in BP-PEG. The salt concentrations in BP-PEG/LiClO₄ complexes were also changed and the results show that maximum conductivity is obtained at [EO]/[Li⁺]≈8. The reasons for these findings are discussed in terms of the number of charge carriers and the mobility of the polymer chain.     

Single Lithium‐Ion Conducting Polymer Electrolytes Based on a Super‐Delocalized Polyanion

A novel single lithium‐ion (Li‐ion) conducting polymer electrolyte is presented that is composed of the lithium salt of a polyanion, poly[(4‐styrenesulfonyl)(trifluoromethyl(S‐trifluoromethylsulfonylimino)sulfonyl)imide] (PSsTFSI^?), and high‐molecular‐weight poly(ethylene oxide) (PEO). The neat LiPSsTFSI ionomer displays a low glass‐transition temperature (44.3 °C; that is, strongly plasticizing effect). The complex of LiPSsTFSI/PEO exhibits a high Li‐ion transference number (t_Li⁺=0.91) and is thermally stable up to 300 °C. Meanwhile, it exhibits a Li‐ion conductivity as high as 1.35×10^?4 S cm^?1 at 90 °C, which is comparable to that for the classic ambipolar LiTFSI/PEO SPEs at the same temperature. These outstanding properties of the LiPSsTFSI/PEO blended polymer electrolyte would make it promising as solid polymer electrolytes for Li batteries.     

Enhanced ionic conductivity in PEO/PMMA glassy miscible blends: Role of nano‐confinement of minority component chains

AC impedance spectroscopy was used to investigate the ionic conductivity of solution cast poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA) blends doped with lithium perchlorate. At low PEO contents (below overlap weight fraction w^*), ionic conductivities are almost low. This could be due to nearly distant PEO chains in blend, which means ion transportation cannot be performed adequately. However, at weight fractions well above w^*, a significant increase in ionic conductivity was observed. This enhanced ionic conductivity mimics the PEO segmental relaxation in rigid PMMA matrix, which can be attributed to the accelerated motions of confined PEO chains in PMMA matrix. At PEO content higher than 20 wt % the conductivity measured at room temperature drops due to crystallization of PEO. However by increasing temperature to temperatures well above the melting point of PEO, a sudden increase of conductivity was observed which was attributed to phase transition from crystalline to amorphous state. The results indicate that some PEO/PMMA blends with well enough PEO content, which are structurally solid, can be considered as an interesting candidate for usage as solid‐state electrolytes in Lithium batteries. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2065–2071, 2010     

Structural and transport characteristics of polyethylene oxide/phenolic resin blend solid polymer electrolytes

Details on the structure and transport characteristics of the solid polymer electrolyte polyethylene oxide (PEO)/lithium salt (LiClO₄) modified by novolac phenolic resin are presented here. From IR spectra it could be concluded that complex formation occurred through multiple interactions between the ether oxygen of PEO–lithium, phenolic lithium, and the phenolic ether oxygen of PEO. The free hydroxyl band in phenolic reflected that phenolic closely interacted with both the PEO polymer and ionic salt. With increasing salt content in PEO, the vibration band corresponding to the ClO anion (～623 cm^?1) displayed growth of a shoulder at ～635 cm^?1, suggesting the formation of Li⁺…ClO₄^? ion pairing. However, in the presence of phenolic, ion‐pairing formation was effectively suppressed, which suggested that the phenolic moiety facilitated a greater degree of LiClO₄ salt dissociation. Activation energy analysis revealed two conducting pathways: one through the amorphous PEO and the other through the PEO/phenolic amorphous matrix. The high ion conductivity originated from effective salt dissociation and the establishment of a new conduction network formed by PEO and phenolic. Furthermore, the structural modification also extended the thermal stability and mechanical strength of the solid polymer electrolyte composite. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3866–3875, 2004     

Brush‐First ROMP of poly(ethylene oxide) macromonomers of varied length: impact of polymer architecture on thermal behavior and Li+ conductivity

The properties of polymeric materials are dictated not only by their composition but also by their molecular architecture. Here, by employing brush‐first ring‐opening metathesis polymerization (ROMP), norbornene‐terminated poly(ethylene oxide) (PEO) macromonomers ( MM‐n , linear architecture), bottlebrush polymers ( Brush‐n , comb architecture), and brush‐arm star polymers ( BASP‐n , star architecture), where n indicates the average degree of polymerization (DP) of PEO, are synthesized. The impact of architecture on the thermal properties and Li⁺ conductivities for this series of PEO architectures is investigated. Notably, in polymers bearing PEO with the highest degree of polymerization, irrespective of differences in architecture and molecular weight (~100‐fold differences), electrolytes with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as an Li⁺ source exhibit normalized ionic conductivities (σ_n) within only 4.9 times difference (σ_n = 29.8 × 10^?5 S cm^?1 for MM‐45 and σ_n = 6.07 × 10^?5 S cm^?1 for BASP‐45 ) at a concentration of Li⁺ r = [Li⁺]/[EO] = 1/12 at 50 °C. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 448–455     

Reciprocated suppression of polymer crystallization toward improved solid polymer electrolytes: Higher ion conductivity and tunable mechanical properties

Solid polymer electrolytes based on lithium bis(trifluoromethanesulfonyl) imide and polymer matrix were extensively studied in the past due to their excellent potential in a broad range of energy related applications. Poly(vinylidene fluoride) (PVDF) and polyethylene oxide (PEO) are among the most examined polymer candidates as solid polymer electrolyte matrix. In this work, we study the effect of reciprocated suppression of polymer crystallization in PVDF/PEO binary matrix on ion transport and mechanical properties of the resultant solid polymer electrolytes. With electron and X‐ray diffractions as well as energy filtered transmission electron microscopy, we identify and examine the appropriate blending composition that is responsible for the diminishment of both PVDF and PEO crystallites. A three‐fold conductivity enhancement is achieved along with a highly tunable elastic modulus ranging from 20 to 200 MPa, which is expected to contribute toward future designs of solid polymer electrolytes with high room‐temperature ion conductivities and mechanical flexibility. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1450–1457     

Amphiphilic polymer gel electrolytes. I. preparation of gels based on poly(ethylene oxide) graft copolymers containing different ionophobic groups

Amphiphilic graft copolymers were prepared via the radical copolymerization of poly(ethylene oxide) (PEO) macromonomers with fluorocarbon or hydrocarbon acrylates in toluene with 2,2′‐azobisisobutyronitrile (AIBN) as an initiator. ¹H NMR spectroscopy confirmed that the composition of the graft copolymers corresponded well to the monomer feed. For gel electrolytes prepared from the amphiphilic copolymers, the nature of the ionophobic parts of the amphiphilic graft copolymers had a great influence on the ion conductivity. Gel electrolytes based on graft copolymers containing fluorocarbon side chains showed significantly higher ion conductivity than electrolytes based on graft copolymers containing hydrocarbon groups. The ambient‐temperature ion conductivity was about 2.6 mS/cm at 20 °C for a gel electrolyte based on an amphiphilic graft copolymer consisting of an acrylate backbone carrying PEO and fluorocarbon side chains. Corresponding gels based on graft copolymers with PEO side chains and hydrocarbon groups showed an ambient‐temperature ion conductivity of about 1.2 mS/cm. The gel electrolytes contained 30 wt % copolymer and 70 wt % 1 M LiPF₆ in an ethylene carbonate/γ‐butyrolactone (2/1 w/w) mixture. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2223–2232, 2001     

Conductivity and characterization of polyurea electrolytes with carboxylic acid

Polyurea, which was synthesized from 4,4′‐diphenylmethane diisocyanate, Jeffamine‐ED2001 (weight‐average molecular weight: 2000), and 3,5‐diaminobanzoic acid (DABA) were doped with lithium perchlorate (LiClO₄) as the polyelectrolyte. Differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, and ⁷Li magic‐angle spinning (MAS) solid‐state NMR were used to monitor changes in the morphology of polyurea electrolytes corresponding to the concentration of LiClO₄ dopants. DSC showed the glass‐transition temperature of the hard and soft segments increases with salt concentration. FTIR indicated the carboxylic group of DABA coordinates with the Li⁺ ion, and the ordered hydrogen‐bonded urea carbonyl groups are destroyed when the salt concentration exceeds 0.5 mmole of LiClO₄ (gPUrea)^?1. The ⁷Li MAS solid‐state NMR investigation of the polyurea electrolytes revealed the presence of two Li⁺ environments at lower temperature. Impedance spectroscopy measurements showed that the conductivity behavior followed the Arrhenius equation, and the maximum conductivity occurred when the crystalline structure of polyurea was disrupted. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 4007–4016, 2003     

Ultraviolet-Cured Semi-Interpenetrating Network Polymer Electrolytes for High-Performance Quasi-Solid-State Lithium Metal Batteries

Solid polymer electrolytes with relatively low ionic conductivity at room temperature and poor mechanical strength greatly restrict their practical applications. Herein, we design semi-interpenetrating network polymer (SNP) electrolyte composed of an ultraviolet-crosslinked polymer network (ethoxylated trimethylolpropane triacrylate), linear polymer chains (polyvinylidene fluoride-co-hexafluoropropylene) and lithium salt solution to satisfy the demand of high ionic conductivity, good mechanical flexibility, and electrochemical stability for lithium metal batteries. The semi-interpenetrating network has a pivotal effect in improving chain relaxation, facilitating the local segmental motion of polymer chains and reducing the polymer crystallinity. Thanks to these advantages, the SNP electrolyte shows a high ionic conductivity (1.12 mS cm⁻¹ at 30 °C), wide electrochemical stability window (4.6 V vs. Li⁺/Li), good bendability and shape versatility. The promoted ion transport combined with suppressed impedance growth during cycling contribute to good cell performance. The assembled quasi-solid-state lithium metal batteries (LiFePO₄/SNP/Li) exhibit good cycling stability and rate capability at room temperature.     

Influence of thermal history and humidity on the ionic conductivity of nanoparticle‐filled solid polymer electrolytes

The crystallinity and conductivity of nanoparticle‐filled solid polymer electrolytes (SPEs) are investigated as a function of thermal history and water content. Our objective is to evaluate how performance is affected by the conditions under which the SPEs are handled and tested. The samples consist of polyethylene oxide (PEO), LiClO₄, and Al₂O₃ nanoparticles. At low humidity, SPEs at ether oxygen to lithium ratios of 8:1 do not crystallize immediately; instead, 3 days are required for crystallization to occur, and this does not depend strongly on the presence of nanoparticles. The conductivity is improved by the addition of nanoparticles at low humidity, but only at an ether oxygen to lithium ratio of 10:1, which corresponds to the eutectic concentration. At high humidity, the recrystallization time is delayed for 3 weeks, and the conductivity increases in both filled and unfilled SPEs beyond that of the low humidity samples. Although we observe that water amplifies the influence of nanoparticles on conductivity, we also find that nanoparticles inhibit water uptake—but only in the presence of lithium. Because Li⁺ strongly absorbs water, this result suggests that nanoparticles may interact directly with Li⁺ ions to prevent water uptake. In filled samples at the eutectic concentration (10:1), more water is absorbed compared to the nanoparticle‐filled 8:1 samples, even though less lithium is present. This suggests that nanoparticles may segregate to lithium‐poor regions in the 10:1 samples, and this scenario is supported by the morphology that would be expected at the eutectic concentration. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1496–1505, 2011     

Conductivities and spectroscopic studies on hyperbranched polyurethane electrolytes

Polymer electrolytes were prepared with hyperbranched polyurethane, linear polyurethane as the host polymer, and lithium perchlorate (LiClO₄) as the ion source. Fourier transform infrared spectra were used to analyze the bonding degree of Li⁺ with carbonyl and ether groups. Raman spectra were applied to analyze the aggregate degree of anion perchlorate ion (ClO). The spectra analysis indicated that the hyperbranched polyurethane could function as a “solvent” for the lithium salt. Also, the conductivity increased with increasing concentration of hyperbranched polymers in the host polymer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 120–126, 2003     

Effects of PEO length and phenyl unit structure on ionic conductivities of the complexes of LiClO4 and alternating copolymers of PEO having various phenyl units in the backbone

A series of copolymers of predominantly poly(ethylene oxide) (PEO) with mono-phenyl (HQ), biphenyl (BP) units, or both of them (HQ/BP) in the backbone were synthesized. The solid polymer electrolytes (SPEs) were prepared from three different types of copolymers (HQ-PEG, BP-PEG, and HQ/BP-PEG) employing lithium perchlorate (LiClO₄) as a lithium salt at a fixed salt concentration of [EO]/[Li⁺]=8. Their ionic conductivities were investigated to exploit the structure–ionic conductivity relationships as a function of structural change in rigid phenyl units and chain length ratio between flexible PEO chain and rigid phenyl units. As more rigid phenyl units were incorporated in the backbone chain, the formation inter- and intra-molecular complex with LiClO₄ became weaker and lower ionic conductivities were observed. And it was also found that higher ionic conductivity is obtained with increasing PEO chain length because inter- and intra-molecular dissociation power of PEO increases.     

Effect of cation exchange capacity on the structure and dynamics of poly(ethylene oxide) in Li+ montmorillonite nanocomposites

Molecular dynamics computer simulations are used to study the structure and dynamics of 1-nm wide films of poly(ethylene oxide) (PEO) confined between mica-type layered silicates of different cation exchange capacities (CEC). The simulation setup mimics experimental systems formed by intercalation of PEO in montmorillonite alumino-silicates with varied inherent charges. It is shown that the presence and population of lithium has a significant influence on the behavior of the system, in addition to the confinement-induced effects caused by the extreme spatial restriction. The structural features of the confined PEO are strongly altered with the number of Li⁺, which determines the polymer/inorganic interactions. The combination of the nanoconfinement and the presence of lithium preclude regular ordered arrangements of PEO, similar to those observed in the bulk unconfined polymer. The segmental dynamics of PEO in confinement are also greatly influenced by the presence of lithium, because of the strong interaction between Li⁺ and the oxygen of the PEO backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3460–3477, 2005     

Lithium Ion Pathway within Li7La3Zr2O12‐Polyethylene Oxide Composite Electrolytes

Polymer–ceramic composite electrolytes are emerging as a promising solution to deliver high ionic conductivity, optimal mechanical properties, and good safety for developing high‐performance all‐solid‐state rechargeable batteries. Composite electrolytes have been prepared with cubic‐phase Li₇La₃Zr₂O₁₂ (LLZO) garnet and polyethylene oxide (PEO) and employed in symmetric lithium battery cells. By combining selective isotope labeling and high‐resolution solid‐state Li NMR, we are able to track Li ion pathways within LLZO‐PEO composite electrolytes by monitoring the replacement of ⁷Li in the composite electrolyte by ⁶Li from the ⁶Li metal electrodes during battery cycling. We have provided the first experimental evidence to show that Li ions favor the pathway through the LLZO ceramic phase instead of the PEO‐LLZO interface or PEO. This approach can be widely applied to study ion pathways in ionic conductors and to provide useful insights for developing composite materials for energy storage and harvesting.     

Clicked (AB)2C‐type miktoarm terpolymers: Synthesis,thermal and self‐assembly properties,and preparation of nanoporous materials

A well‐defined (PEO‐PS)₂‐PLA miktoarm terpolymer ( 1 ) was synthesized by stepwise click reactions of individually prepared poly(ethylene oxide) (PEO), polystyrene (PS, polymerized by atom transfer radical polymerization), and polylactide (PLA, polymerized by ring‐opening polymerization) blocks. As characterized by differential scanning calorimetry and small‐angle X‐ray scattering techniques, the terpolymer self‐assembled into a hexagonal columnar structure consisting of PLA/PEO cylindrical cores surrounded by PS chains. In contrast, the ion‐doped sample ( 1‐Li⁺ ) with lithium concentration per ethylene oxide = 0.2 exhibited a three‐phase lamellar structure, which was attributed to the microphase separation between PEO and PLA blocks and to the conformational stabilization of the longest PLA chain. The two‐phase columnar morphology before the ion doping was used to prepare a nanoporous material. PLA chains in the cylindrical core region were hydrolyzed by sodium hydroxide, producing nanopores with a pore diameter of about 14 nm. The resulted nanoporous material sank to the bottom in water, because of water‐compatible PEO chains on the walls. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Vacancy‐Controlled Na+ Superion Conduction in Na11Sn2PS12

Highly conductive solid electrolytes are crucial to the development of efficient all‐solid‐state batteries. Meanwhile, the ion conductivities of lithium solid electrolytes match those of liquid electrolytes used in commercial Li⁺ ion batteries. However, concerns about the future availability and the price of lithium made Na⁺ ion conductors come into the spotlight in recent years. Here we present the superionic conductor Na₁₁Sn₂PS₁₂, which possesses a room temperature Na⁺ conductivity close to 4 mS cm^?1, thus the highest value known to date for sulfide‐based solids. Structure determination based on synchrotron X‐ray powder diffraction data proves the existence of Na⁺ vacancies. As confirmed by bond valence site energy calculations, the vacancies interconnect ion migration pathways in a 3D manner, hence enabling high Na⁺ conductivity. The results indicate that sodium electrolytes are about to equal the performance of their lithium counterparts.     

Highly concentrated polycarbonate‐based solid polymer electrolytes having extraordinary electrochemical stability

Solid polymer electrolytes (SPEs) are compounds of great interest as safe and flexible alternative ionics materials, particularly suitable for energy storage devices. We study an unusual dependence on the salt concentration of the ionic conductivity in an SPE system based on poly(ethylene carbonate) (PEC). Dielectric relaxation spectroscopy reveals that the ionic conductivity of PEC/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) electrolyte continues to increase with increasing salt concentration because the segmental motion of the polymer chains is enhanced by the plasticizing effect of the imide anion. Fourier transfer‐infrared (FTIR) spectroscopy suggests that this unusual phenomenon arises because of a relatively loose coordination structure having moderately aggregated ions, in contrast to polyether‐based systems. Comparative FTIR study against PEC/lithium perchlorate (LiClO₄) electrolytes suggests that weak ionic interaction between Li and TFSI ions is also important. Highly concentrated electrolytes with both reasonable conductivity and high lithium transference number (t₊) can be obtained in the PEC/LiTFSI system as a result of the unusual salt concentration dependence of the conductivity and the ionic solvation structure. The resulting concentrated PEC/LiTFSI electrolytes have extraordinary oxidation stability and prevent any Al corrosion reaction in a cyclic voltammetry. These are inherent effects of the highly concentrated salt. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 2442–2447     

Li1.3Al0.3Ti1.7(PO4)3 filler effect on (PEO)LiClO4 solid polymer electrolyte

Composite polymer electrolyte (CPE) films consisting of PEO, LiClO₄, and Li_1.3Al_0.3Ti_1.7(PO₄)₃ with fixed EO/Li = 8 but different relative compositions of the two lithium salts were prepared by the solution casting method. The CPE films were characterized using SEM, DSC, electrical impedance spectroscopy (EIS), and ion transference number measurement. It was found that the incorporation of LiClO₄ and Li_1.3Al_0.3Ti_1.7(PO₄)₃ into PEO by keeping EO/Li = 8 reduced the crystallinity of PEO from 50.34% to the range of 3.57–15.63% depending upon the relative composition of the two salts. The room temperature impedance spectra of the CPE films all exhibited a shape of depressed semicircle in the high frequency range and inclined line in the low frequency range, but the high temperature ones were mainly inclined lines. The Li⁺ ionic conductivity of the CPE films mildly increased and then decreased with increasing Li_1.3Al_0.3Ti_1.7(PO₄)₃ content, and the maximum conductivities were obtained at Li_1.3Al_0.3Ti_1.7(PO₄)₃ content of 15 wt % for all measuring temperatures, for example, 1.378 × 10^?3 S/cm at 100 °C and 1.387 × 10^?5 S/cm at 25 °C. The temperature dependence of the ionic conductivity of the CPE films follows the Vogel–Tamman–Fulcher (VTF) equation The pseudo activation energies (E_a) were rather low, 0.053–0.062 eV, indicating an easy migration of Li⁺ in the amorphous phase dominant PEO. The pre‐exponent constant A and ion transference number t_Li+ were found to have a similar variation tendency with increasing Li_1.3Al_0.3Ti_1.7(PO₄)₃ content and reached their maximums also at Li_1.3Al_0.3Ti_1.7(PO₄)₃ content of 15 wt %. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 743–751, 2005     

Single-ion and salt conductor polymer electrolytes based on poly(4-vinylpyridine) quaternized with poly(ethylene oxide) side chains

A new type of single-ion conductor with fixed cation was synthesized by spontaneous anionic polymerization of 4-vinylpyridine in the presence of short polyethylene oxide ( PEO ) chains as alkylating agents. These comblike polymers have low T_gs and are amorphous with the shorter PEO s. Their conductivities are unaffected by the nature of the anion ( Br ⁻, ClO ₄⁻, and tosylate) and are controlled by the free volume and the mobility of the pendant cation. By comparison of the results at constant free volume, it is shown that the charge density decreases with the increasing length of pendant PEO demonstrating that PEO acts only as a plasticizing agent. Best conductivity results (σ = 10⁻⁵ S cm⁻¹ at 60°C) are obtained with PEO side chains of molecular weight 350. With this sample, the conductivity in the presence of various amounts of added salt (LiTFSI) was studied. A best value of 10⁻⁴ S cm⁻¹ at 60°C is obtained with a molar ratio EO/Li of 10. It is shown that, over the range of examined concentrations (0.2–1.3 mol Li kg⁻¹), the reduced conductivity σ_r/c increases linearly with increasing salt concentration showing that the ion mobility increases continuously. Such behavior is quite unusual since in this concentration range a maximum is generally observed with PEO systems. To interpret this result and by analogy with the behavior of this type of polymer in solution, it is proposed that the conformation of these polymers in the solid state is segregated with the P4VP skeleton more or less confined inside the dense coils surrounded by the PEO side chains. Under the influence of the increasing salt concentration, this microphase separation vanishes progressively: The LiTFSI salt exchanges with the tosylate anions and acts as a miscibility improver agent. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2719–2728, 1997     

Salt‐induced microphase separation of amorphous dendritic poly(ethylene oxide)‐block‐linear polystyrene copolymers

We prepared two block copolymers 1 and 2 consisting of a third‐generation dendron with poly(ethylene oxide) (PEO) peripheries and a linear polystyrene (PS) coil. The PS molecular weights were 2000 g/mol and 8000 g/mol for 1 and 2 , respectively. The differential scanning calorimetry (DSC) data indicated that neither of the block copolymers showed glass transition, implying that there was no microphase separation between the PEO and PS blocks. However, upon doping the block copolymers with lithium triflate (lithium concentration per ethylene oxide unit = 0.2), two distinct glass transitions were seen, corresponding to the salt‐doped PEO and PS blocks, respectively. The morphological analysis using small angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM) demonstrated that a hexagonal columnar morphology was induced in salt‐doped sample 1‐Li⁺ , whereas the other sample ( 2‐Li⁺ ) with a longer PS coil revealed a lamellar structure. In particular, in the SAXS data of 2‐Li⁺ , an abrupt reduction in the lamellar thickness was observed near the PS glass transition temperature (T_g), in contrast to the SAXS data for 1‐Li⁺ . This reduction implies that there is a lateral expansion of the molecular section in the lamellar structure, which can be interpreted by the conformational energy stabilization of the long PS coil above T_g. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2372–2376, 2010