Morphology Of Block Copolymers Research Articles

Topology Affecting Block Copolymer Nanoassemblies: Linear Block Copolymers versus Star Block Copolymers under PISA Conditions

Linear and star block copolymer (BCP) nanoassemblies of [poly(4-vinylpyridine)-block-polystyrene]n ([P4VP-b-PS]n) with different arm numbers have been synthesized by RAFT dispersion polymerization under formulation of polymerization-induced self-assembly (PISA). All RAFT dispersion polymerizations employing mono- and multifunctional macromolecular chain transfer agents proceed with similar polymerization kinetics. The size and/or morphology of [P4VP-b-PS]n nanoassemblies are firmly correlative to arm number n, and star [P4VP-b-PS]n BCPs have more complex morphology than the linear counterpart. Several interesting morphologies of star BCPs including small-sized vesicles and porous nanospheres have been synthesized, and they are compared with those of the linear counterpart. Our research indicates that topology is a significant parameter to dedicate the size and morphology of star BCP nanoassemblies under PISA conditions.

Interfacial morphologies and associated processes of multicomponent polymers

This review describes contemporary advancements in the study of interfacial morphologies and associated processes of multicomponent polymers. A particular emphasis is placed on the use of three-dimensional (3D) microscopy, for example, transmission electron microtomography (TEMT) and laser scanning confocal microscopy (LSCM). The time evolution of a spinodal interface during the phase separation of a polymer blend was followed by LSCM. The obtained 3D interfacial morphology was analyzed by differential geometry. The scalability was tested using curvature distributions. 3D nanoimaging, that is, TEMT, was applied to examine the stability and dynamics of complex block copolymer (BCP) morphologies, and novel structural data were directly assessed according to the 3D volume data. This review also examines two essential developments in the time-dependent in situ electron tomography of polymer materials to study the dynamic processes of BCPs. The 3D microscopy-based structural information renders an important perspective into the studies of nonlinear nonequilibrium occurrences as well as the statistical physics of long-chain-bearing moieties.

Synthesis, Thermal Properties, and Morphologies of Amphiphilic Brush Block Copolymers with Tacticity-Controlled Polyether Main Chain

A series of brush block copolymers (BBCPs) consisting of poly(decyl glycidyl ether) (PDGE) and poly(10-hydroxyldecyl glycidyl ether) (PHDGE) blocks, having four different types of chain tacticities, i.e., [at-PDGE]-b-[at-PDEGE], [at-PDGE]-b-[it-PDEGE], [it-PDGE]-b-[at-PDEGE], and [it-PDGE]-b-[it-PDEGE], where the it and at represent the isotactic and atactic chains, respectively, were prepared by t-Bu-P4-catalyzed sequential anionic ring-opening polymerization of glycidyl ethers followed by side-chain modification. The corresponding homopolymers, i.e., at-PDGE, it-PDGE, at-PHDGE, and it-PHDGE, were also prepared for comparison with the BBCPs. The PDGE homopolymers were significantly promoted in the phase transitions and morphological structure formation by the isotacticity formation. In particular, it-PDGE was found to form only a horizontal multibilayer structure with a monoclinic lattice in thin films, which was driven by the bristles’ self-assembling ability and enhanced by the isotacticity. However, t...

Formation of Anisotropic Liquid Crystalline Nanoparticles via Polymerization-Induced Hierarchical Self-Assembly.

Polymeric nanoparticles (NPs) containing liquid crystalline (LC) mesogens with tunable anisotropic morphologies have applications in various fields, but their preparation typically suffers from tedious and low-throughput approaches. Here we present an efficient route to the preparation of anisotropic morphologies of azobenzene-containing block copolymers (BCPs) at high solids content via a polymerization-induced hierarchical self-assembly in ethanol. Various anisotropic NPs, including cuboids, short belts, lamellae, and ellipsoidal vesicles, have been obtained in a remarkably broad range of BCP compositions. The NPs exhibit a smectic phase with ordered stripes when observed under TEM. This internal LC ordering plays a significant role on the formation of these intriguing anisotropic morphologies. Morphological transitions from anisotropic to isotropic spheres can be obtained upon UV illumination due to the photoresponsive properties of the azobenzene mesogens. This work significantly expands the scope of accessible morphologies in PISA and suggests that the under explored LC BCPs may have an impactful role in the PISA field.

Diffusion of Molecular and Macromolecular Polyolefin Probes in Cylindrical Block Copolymer Structures As Observed by High Temperature Single Molecule Fluorescence Microscopy

Highly sensitive fluorescence microscopy methods allow for the observation of single bright fluorescent probes. Analysis of their trajectories gives access to the mode of diffusion and the heterogeneity in motion of individual probes. Especially for structured soft materials, this information is of paramount importance for a multitude of possible applications such as nanoelectronics, nanophotonics, or nanomembrane technology. Compared to biological systems, utilization for materials research faces the challenge that relevant processes occur at elevated temperature, often above 100 °C, and that fluorescence labeling procedures are yet less evolved. We investigated the motion of single probes in block copolymer morphologies from room temperature to over 100 °C with a custom-made heating device to allow for such high temperatures without damaging the optics of a commercial optical microscope and also with the possibility to measure under a nitrogen atmosphere to reduce photobleaching of the dyes. Apart from ...

Diblock-Copolymer-Based Composites for Tire-Tread Applications with Improved Filler Network Topology

We present in this Letter the results of a study focusing on vulcanized poly(butadiene–styrene butadiene rubber) (PB–SBR) diblock copolymers in the microphase-separated state filled with various amounts of silica nanoparticles. It is demonstrated that the microphase separation of PB and SBR blocks is preserved in composites with a silica mass content of ≤60 parts per hundred rubber (phr). The only effect of silica incorporation is a more restricted long-range order of the block copolymer morphology. The most interesting finding is, however, that through mechanical mixing the silica nanoparticles are highly selectively incorporated in the SBR phase up to high filler contents. This opens new opportunities toward a rational design of the filler network in composites with self-assembled elastomer matrixes and results in advantageous mechanical properties for tire-tread applications.

Ordering and Grain Growth in Charged Block Copolymer Bulk Films: A Comparison of Solvent‐Related Processes

AbstractWhile prior efforts have demonstrated that the morphologies of block copolymer (BC) bulk films can be controlled through judicious chemical design and thermal annealing, recent interest has focused on regulating the orientation of BC nanostructures and minimizing defects. Thermal processes developed to achieve this purpose for nonpolar BCs are not, however, suitable for orienting microphase‐ordered BCs composed of at least one block with charged moieties that can form thermally stable ionic clusters. To overcome this challenge, we have previously applied solvent‐vapor (SV) annealing to block ionomer (BI) bulk films composed of midblock‐sulfonated pentablock copolymers and established that this approach yields highly ordered morphologies that display evidence of improved in‐plane orientation. Here, we employ small‐angle X‐ray scattering to compare the effectiveness of three solvent‐related processes–SV annealing, SV permeation, and SV sorption–on BI ordering and grain growth, and offer explanations for observed differences on the basis of thermodynamic‐ and transport‐related considerations. Differences in the experimental design of these solvent‐related processes are found to affect nanostructural development, as evidenced by the extent of in‐plane grain growth.

Metallopolymer-Based Block Copolymers for the Preparation of Porous and Redox-Responsive Materials.

Metallopolymers are a unique class of functional materials because of their redox-mediated optoelectronic and catalytic switching capabilities and, as recently shown, their outstanding structure formation and separation capabilities. Within the present study, (tri)block copolymers of poly(isoprene) (PI) and poly(ferrocenylmethyl methacrylate) having different block compositions and overall molar masses up to 328 kg mol-1 are synthesized by anionic polymerization. The composition and thermal properties of the metallopolymers are investigated by state-of-the-art polymer analytical methods comprising size exclusion chromatography, 1H NMR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. As a focus of this work, excellent microphase separation of the synthesized (tri)block copolymers is proven by transmission electron microscopy, scanning electron microcopy, energy-dispersive X-ray spectroscopy, small-angle X-ray scattering measurements showing spherical, cylindrical, and lamellae morphologies. As a highlight, the PI domains are subjected to ozonolysis for selective domain removal while maintaining the block copolymer morphology. In addition, the novel metalloblock copolymers can undergo microphase separation on cellulose-based substrates, again preserving the domain order after ozonolysis. The resulting nanoporous structures reveal an intriguing switching capability after oxidation, which is of interest for controlling the size and polarity of the nanoporous architecture.

Introduction to Editorial Board Member: Professor Paula T. Hammond

In this issue of Bioengineering and Translational Medicine, we are pleased to introduce our Editorial Board Member, Professor Paula T. Hammond. Prof. Hammond is the David H. Koch Chair Professor of Engineering and the Head of the Department of Chemical Engineering at the Massachusetts Institute of Technology (MIT). Prof. Hammond received her BS degree from MIT in Chemical Engineering, her MS degree from the Georgia Institute of Technology, and her PhD degree from MIT. Over the past two decades, Professor Hammond's research has made deep and impactful contributions in the fields of synthetic polymers, nanomedicine, and materials assembly. Professor Hammond is a leader in the use of molecular interactions, which include electrostatic and hydrogen-bonding forces, to generate “layer-by-layer” deposited functional materials with highly controlled microscale and nanoscale structures on a broad range of surfaces as a means to create ordered architecture.1-3 Her research has leveraged these nanoscale forces, inherent to many synthetic and natural materials, toward developing a range of new biochemical and electrochemical materials with synergistic functionality that are well beyond the capacity of individual materials. Professor Hammond's research draws on and extends concepts of thermodynamics and self-assembly in which the basis of the approach is the use of secondary, or nonspecific interactions, in combination with steric repulsion and electrostatic interactions, to direct the deposition of molecules and larger scale materials systems onto activated surfaces in a stepwise layer-by-layer approach. She has pioneered the development and application of this technology to generate controlled release thin film coatings for biomedical implants that address tissue regeneration,4 wound healing,5 and transdermal delivery from microneedle platforms,6 to nanoparticle drug carriers for drug, gene, and siRNA delivery.7-9 Professor Hammond has also extended the applications of self-assembled materials to electrochemical energy devices,10 including photovoltaics11 and fuel cells.12 Another major research area in Professor Hammond's group focuses on nanoscale self-assembly through the design of functionalized block copolymers. Block copolymers, which consist of two or more covalently bound polymer segments of different chemical composition, are known for their ability to microphase separate and organize into mesophase structures on nanometer length scales in the bulk state, and at surfaces and interfaces, based on chemical differences between blocks. Professor Hammond's research has demonstrated the role of controlling the molecular architecture on the nanoscale in the ordering of block copolymer morphology, particularly for copolymer systems with asymmetric (irregular or nonlinear) blocks. Professor Hammond's research has investigated the development and application of dendritic-linear block copolymers as nanoencapsulants for targeted drug delivery.13 Professor Hammond has led a remarkable career as a researcher and educator. Her research has been published in over 300 journal articles and book chapters, and has been heavily cited, with more than 21,000 citations. In recognition of these contributions to materials chemistry and nanomedicine, Prof. Hammond has been presented with numerous awards and honors. She has been elected to the National Academy of Engineering (2017), the National Academy of Medicine (2016), and the American Academy of Arts and Sciences (2013). She is an elected Fellow of the American Physical Society, the American Institute of Biological and Medical Engineers, and the American Chemical Society Polymer Division. She is the recipient of the AIChE Charles M. A. Stine Award (2013) in recognition of outstanding contributions to the field of materials science and engineering, and the Alpha Chi Sigma Award (2014) for Chemical Engineering Research. Professor Hammond has been featured numerous times in the top 100 cited materials scientists. In addition to research and teaching excellence, Prof. Hammond has had a deep interest for administrative leadership. At MIT, she co-founded the MIT Institute for Soldier Nanotechnology. She served as the Executive Officer of the Chemical Engineering Department of MIT (2008–2011) and currently serves as the department chair. Professor Hammond describing the spray layer-by-layer technology to President Barack Obama during the President's visit to MIT on October 23, 2009 Source. MIT Spring 2010 Chemical Engineering Newsletter (http://web.mit.edu/cheme/alumni/newsletter/XCurrentsSpring10.pdf) Group photo at the 15 year Hammond Lab reunion on June 4, 2011 Photo courtesy of the Hammond Group

Microphase‐Separated Morphology and Liquid Crystal Orientation in Block Copolymers Comprising a Main‐Chain Liquid Crystalline Central Segment Connected to Side‐Chain Liquid Crystalline Segments at Both Ends

AbstractThe self‐assembly behavior of ABA triblock copolymers comprising side‐chain (SC) liquid crystalline (LC) polymer (A blocks) and a main‐chain (MC) LC polyester (B block) is investigated for SCLC segment volume fractions (ϕ) ranging from 22% to 81%. At ϕ = 81% and 65%, the MCLC segments form cylinders and spheres, respectively, embedded in an SCLC matrix. At ϕ ≤ 56%, block copolymers form lamellar microdomains in which each segment forms smectic layers parallel to the lamellae. Whereas MCLC segments are mostly extended along the lamella normal but are folded to fit within the lamellae, the SCLC segment backbone is more elongated, traversing the smectic layers. Such backbone dimensions and mesogens' orientation in the SCLC segment are explained in light of the small interfacial area with the B5 segment, which is conserved even when the SCLC segment is in the isotropic liquid state.

Nonclassical Spherical Packing Phases Self-Assembled from AB-Type Block Copolymers.

Among the various ordered morphologies self-assembled from block copolymers, the spherical packing phases are particularly interesting because they resemble the familiar atomic crystals. The commonly observed spherical morphology of block copolymers is the body-centered-cubic phase. Recently, a number of novel spherical packing phases, i.e., the complex Frank-Kasper phases originally obtained in metallic alloys, have been observed in block copolymer melts. Theoretical studies have revealed that conformational asymmetry of the different blocks provides a key mechanism to stabilize the Frank-Kasper phases. Furthermore, local segregation of different copolymers in blends of diblock copolymers and copolymer architectures provides additional mechanisms to enhance the stability of the complex ordered phases. In this Viewpoint we summarize recent advances in our understanding of the formation of the nonclassical spherical packing phases in AB-type block copolymers, emphasizing the formation mechanisms of these fascinating complex ordered structures.

Effects of Lateral and Terminal Chains of X-Shaped Bolapolyphiles with Oligo(phenylene ethynylene) Cores on Self-Assembly Behaviour. Part 1: Transition between Amphiphilic and Polyphilic Self-Assembly in the Bulk.

Polyphilic self-assembly leads to compartmentalization of space and development of complex structures in soft matter on different length scales, reaching from the morphologies of block copolymers to the liquid crystalline (LC) phases of small molecules. Whereas block copolymers are known to form membranes and interact with phospholipid bilayers, liquid crystals have been less investigated in this respect. Here, series of bolapolyphilic X-shaped molecules were synthesized and investigated with respect to the effect of molecular structural parameters on the formation of LC phases (part 1), and on domain formation in phospholipid bilayer membranes (part 2). The investigated bolapolyphiles are based on a rod-like π-conjugated oligo(phenylene ethynylene) (OPE) core with two glycerol groups being either directly attached or separated by additional ethylene oxide (EO) units to both ends. The X-shape is provided by two lateral alkyl chains attached at opposite sides of the OPE core, being either linear, branched, or semiperfluorinated. In this report, the focus is on the transition from polyphilic (triphilic or tetraphilic) to binary amphiphilic self-assembly. Polyphilic self-assembly, i.e., segregation of all three or four incorporated units into separate nano-compartments, leads to the formation of hexagonal columnar LC phases, representing triangular honeycombs. A continuous transition from the well-defined triangular honeycomb structures to simple hexagonal columnar phases, dominated by the arrangement of polar columns on a hexagonal lattice in a mixed continuum formed by the lipophilic chains and the OPE rods, i.e., to amphiphilic self-assembly, was observed by reducing the length and volume of the lateral alkyl chains. A similar transition was found upon increasing the length of the EO units involved in the polar groups. If the lateral alkyl chains are enlarged or replaced by semiperfluorinated chains, then the segregation of lateral chains and rod-like cores is retained, even for enlarged polar groups, i.e., the transition from polyphilic to amphiphilic self-assembly is suppressed.

Inorganic Nanoparticle Induced Morphological Transition for Confined Self-Assembly of Block Copolymers within Emulsion Droplets.

Recently, it has been reported that the incorporation of functional inorganic nanoparticles (NPs) into the three-dimensional (3D) confined self-assembly of block copolymers (BCPs) creates the unique nanostructured hybrid composites, which can not only introduce new functions to BCPs but also induce some interesting morphological transitions of BCPs. In the current study, we systematically investigate the cooperative self-assembly of a series of size-controlled and surface chemistry-tunable gold nanoparticles (AuNPs) and polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) diblock copolymer within the emulsion droplets. The influences of the size, content, and surface chemistry of the AuNPs on the coassembled nanostructures as well as the spatial distribution of AuNPs in the hybrid particles are examined. It is found that the size and content of the AuNPs are related to the entropic interaction, while the surface chemistry of AuNPs is related to the enthalpic interaction, which can be utilized to tailor the self-assembled morphologies of block copolymer confined in the emulsion droplets. As the content of PS-coated AuNPs increases, the morphology of the resulting AuNPs/PS-b-P2VP hybrid particles changes from the pupa-like particles to the bud-like particles and then to the onion-like particles. However, a unique morphological transition from the pupa-like particles to the mushroom-like particles is observed as the content of P4VP-coated AuNPs increases. More interestingly, it is observed that the large AuNPs are expelled to the surface of the BCP particles to reduce the loss in the conformational entropy of the block segment, which can arrange into the strings of necklaces on the surfaces of the hybrid particles.

Optical Imaging of Large Gyroid Grains in Block Copolymer Templates by Confined Crystallization.

Block copolymer (BCP) self-assembly is a promising route to manufacture functional nanomaterials for applications from nanolithography to optical metamaterials. Self-assembled cubic morphologies cannot, however, be conveniently optically characterized in the lab due to their structural isotropy. Here, the aligned crystallization behavior of a semicrystalline-amorphous polyisoprene-b-polystyrene-b-poly(ethylene oxide) (ISO) triblock terpolymer was utilized to visualize the grain structure of the cubic microphase-separated morphology. Upon quenching from a solvent swollen state, ISO first self-assembles into an alternating gyroid morphology, in the confinement of which the PEO crystallizes preferentially along the least tortuous pathways of the single gyroid morphology with grain sizes of hundreds of micrometers. Strikingly, the resulting anisotropic alignment of PEO crystallites gives rise to a unique optical birefringence of the alternating gyroid domains, which allows imaging of the self-assembled grain structure by optical microscopy alone. This study provides insight into polymer crystallization within a tortuous three-dimensional network and establishes a useful method for the optical visualization of cubic BCP morphologies that serve as functional nanomaterial templates.

Intradomain Textures in Block Copolymers: Multizone Alignment and Biaxiality.

Block copolymer (BCP) melt assembly has been studied for decades, focusing largely on self-organized spatial patterns of periodically ordered segment density. Here, we demonstrate that underlying the well-known composition profiles (i.e., ordered lamella, cylinders, spheres, and networks) are generic and heterogeneous patterns of segment orientation that couple strongly to morphology, even in the absence of specific factors that promote intra or interchain segment alignment. We employ both self-consistent field theory and coarse-grained simulation methods to measure polar and nematic order parameters of segments in a freely jointed chain model of diblock melts. We show that BCP morphologies have a multizone texture, with segments predominantly aligned normal and parallel to interdomain interfaces in the respective brush and interfacial regions of the microdomain. Further, morphologies with anisotropically curved interfaces (i.e., cylinders and networks) exhibit biaxial order that is aligned to the principal curvature axes of the interface.

Synthesis and copolymerization of azidomethyl-substituted oxetanes: the morphology of statistical block copolymers

3,3-Bis(azidomethyl)oxetane and 3-azidomethyl-3-methyloxetane were obtained by bromination of pentaerythritol and metriol with a mixture of hydrobromic, acetic, and sulfuric acids, followed by cyclization in the presence of a phase-transfer catalyst TBAB, with the formation of oxetane ring and replacement of bromide substituents with azide ions. The copolymerization reaction of 3,3-bis-(azidomethyl)oxetane and 3-azidomethyl-3-methyloxetane was performed in the presence of a catalytic system prepared from triisobutylaluminum and water. The methods of small-angle and wide-angle X-ray diffraction analysis were used to determine the amorphous-crystalline and domain structures of the synthesized copolymers. We also present data about conformational and relaxation transitions in these statistical copolymers.

Influence of Carbon Nanotubes on the Morphology and Properties of Styrene‐Butadiene Based Block Copolymers

SummaryStructure property correlations in a styrene‐butadiene star block copolymer melt mixed with varying amounts of multiwalled carbon nanotubes (MWCNTs) were evaluated. The MWCNTs are well dispersed within the matrix and do not significantly impact the star block copolymer morphology or the glass transition temperature. The electrical percolation threshold was found to be at ∼1 wt% of MWCNT concentration. A distinct increase in Young's modulus could be observed at a nanofiller content of 0.1 wt% while maintaining the elastomeric matrix property profile, an observation in tune with the rule‐of‐mixture prediction. Additionally the existence of double yielding was detected in these nanocomposites with a pronounced first yield point indicating a significant enhancement of stiffness in composites with low MWCNT content. Analysis of elastic moduli using Halpin‐Tsai and two‐phase Takayanagi model revealed a matrix‐controlled elastic response without any interfacial contribution due to MWCNT incorporation.

Asymmetric supramolecular double-comb diblock copolymers: From plasticization, to confined crystallization, to breakout

The combination of asymmetric P4VP-b-PAPI diblock copolymers (i.e. fP4VP≠fPAPI) and 3-NDP surfactants in hydrogen-bonded [poly(4-vinylpyridine)-block-poly(N-acryloylpiperidine)](3-nonadecylphenol)x (P4PA(3-NDP)x) supramolecular double-comb diblock copolymers could potentially result in rather interesting morphologies. However, plasticization of the copolymer and the ability of 3-NDP to crystallize were found to affect their self-assembly significantly. In general, for high comb densities x, the complex's tendency to crystallize and its preference to form a flat interface dominated microphase separation. Lower values of x on the other hand gave uneven distribution of 3-NDP, resulting in a higher glass transition temperature of the P4VP block. Crystallization of 3-NDP's aliphatic tails was therefore in most cases restricted to the preferential PAPI microdomains, thereby maintaining the large length scale block copolymer morphology that was already present in the melt. Such behavior is identical to self-assembly of linear semicrystalline diblock copolymers, as in these type of systems structure formation depends on the segregation strength and relative magnitude of the order-disorder transition (TODT), Tg and Tc, leading to mechanisms like confined crystallization or breakout.

Effect of block copolymer morphology on crystallization and water transport

The effect of block copolymer morphology on polymer crystallization and water sorption was investigated using two amphiphilic block copolymers with minority hydrophilic phase. Such polymers have many potential membrane applications, including CO2 capture and water purification. A model block copolymer chemistry comprising polystyrene and poly(ethylene oxide) (PEO) is used in this work. Both block copolymers have strongly phase-separated order, one with lamellar morphology and another with cylindrical morphology. In addition to the block copolymer structure, the PEO phase is semicrystalline at room temperature. The block copolymer structure has dramatic consequences for the degree of PEO crystallinity even in the absence of water. Furthermore, the crystallinity is affected by water sorption. PEO melting and degree of crystallinity were determined as a function of water content. Water solubility was measured between 35 and 75 °C. Interestingly, water sorption properties are dictated almost exclusively by the amorphous PEO volume fraction, being low in the semicrystalline state (below 55 °C) and higher in the amorphous state (above 55 °C). At 55 °C, crystallite dissolution is observed with increasing water solubility. Water diffusion coefficient was also measured; it decreases monotonically with increasing water content. This concentration dependence of diffusion is explained by water clustering, which increases with increasing water content. In addition to block copolymer morphology playing a major role in PEO crystallinity, it has a significant effect on water diffusion in the amorphous polymers and is of practical importance as investigations at elevated temperature are not possible with homopolymer PEO.

Trade-Off Between Transport and Mechanical Properties in Ion-Containing Block Copolymers with Different Self-Assembled Morphologies: A Comparison Study Between Lamellar and Inverse-Hexagonal

Both transport and mechanical performances are required for ion-containing polymers to be successfully used in ion-conducting applications such as fuel cells, actuators and electrodialysis. Phase-separated structure with ion and non-ion domains has been proposed to meet this requirement because these two domains can accommodate the ion and solvent transport and provide mechanical support respectively. The self-assembling nature of block copolymers is therefore used to create ion-containing polymers with well-defined phase-separated morphologies. The morphologies with continuous ion-domain are usually designed to enhance ion transport (1), however more attention may be needed on the trade-off between transport and mechanical properties. We have found out that the mechanical property is poor for some morphologies with continuous ion domain even though the ion domain is still the minor phase compared to the non-ion domain. Due to the electrostatic ion interaction, ion-containing block copolymers display more complicated phase behaviors and generate morphologies beyond that of neutral copolymers (2). Among them, inverse-hexagonal (HEX) structures have been widely prepared (3-5). It has the major non-ion block form the ‘bulk-like’ cylinders residing in the ‘surface-like’ minor ion phase. Our experimental observation indicated that this inverse-HEX morphology may suffer from excessive water swelling when placed in liquid water environment. In our work, the ion-containing block copolymer under study was supposed to form lamellar morphology according to the block copolymer phase diagram, however it generated a mixture of lamellar and inverse-HEX morphologies when casting from a polar solvent. The formation of inverse-HEX was suppressed when adding a little nonpolar solvent for casting. These two morphologies were imaged by TEM as shown in Figure 1. They are both in principle ‘percolating’ structures for ion transport. Although the membrane with a mixture of lamellar and HEX structures did display higher ion-domain connectivity than the pure-lamellar one as per our preliminary dynamic tension test, its ion conductivity under low water activity (in water vapor) and its water vapor transport flux are very close to the pure-lamellar one. This inconsistency may be because of the larger ion to non-ion interface within the inverse-HEX structure, resulting in more interface resistance. Only under high water activities (more than 0.95), the one with inverse-HEX displayed larger conductivity than the pure-lamellar one, probably due to more effective swelling of the hydrophilic phase for the former. And if the water vapor transport was measured with liquid water contacting one side of the membrane, the one with inverse-HEX had larger flux. Water sorption experiment showed that the one with HEX morphology swell more than the pure-lamellar one. And we actually observed the HEX membrane broke apart after placed in liquid water for 2 month while the pure-lamellar one was still intact. Thermodynamic swelling model considering both interface energy and elastic energy is being developed to explain the difference between inverse-HEX and lamellar morphologies. (1) Arges, C. and Kambe, Y. et. al. Realizing the Potential of Micro-Phase Separated Block Copolymer Electrolytes: Ion Domain Connectivity Plays a Prominent Role in Ion Conduction. ECS Transactions. 2016, 75(14), 1013-1020 (2) Sing, C.; Zwanikken, J.; Cruz, M. D. La. Electrostatic Control of Block Copolymer Morphology. Nat. Mater. 2014, 13(7), 694–698 (3) Kim, O.; Shin, T. J.; Park, M. J. Fast Low-Voltage Electroactive Actuators Using Nanostructured Polymer Electrolytes. Nat. Commun. 2013, 4, 2208 (4) Mineart, K. P.; Lee, B.; Spontak, R. J. A Solvent-Vapor Approach toward the Control of Block Ionomer Morphologies. Macromolecules 2016, 49 (8), pp 3126–3137 (5) Zheng, W.; Cornelius, C. J. Solvent Tunable Multi-Block Ionomer Morphology and Its Relationship to Modulus, Water Swelling, Directionally Dependent Ion Transport, and Actuator Performance. Polymer. 2016, 103, 104–111 Figure 1