Polymer-rich Regions Research Articles

Preparation of nanoporous poly (L-lactic acid) microspheres with controllable morphology via thermally-induced phase separation

This article describes a facile method to prepare nanoporous poly (l-lactic acid) microspheres via a thermally-induced phase separation method with controllable diameters. It was found that the morphology and diameter of PLLA microspheres were easily controlled by adjusting solvent ratio, quenching temperature, and PLLA concentrations. The results revealed that by using a ternary solvent system consisting of 1,3-dioxolane as a good solvent, 2-butanone as mid-solvent, and water as a poor solvent, the diameter of PLLA microspheres can be easily controlled by changing the ratio of 1,3-dioxolane and water. The diameter of PLLA microspheres prepared ranged from 28.8 ± 5.9 μm to 63.8 ± 12.5 μm. Moreover, the evolution of PLLA spherulitic structures grown from polymer solution was confirmed as well through varying solvent ratios and PLLA concentrations. The presence of water as a non-solvent governed the phase separation mechanism of the phase separation process. At the same time, the diameter of the spherulites is affected by the ratio of 1,3-dioxolane controlling the polymer crystallization process in the polymer-rich region. Interestingly, the surface of these spherulites contains nanopores due to the stacking of lamellar crystals of PLLA during polymer crystallization which contributed to its superhydrophobicity and superoleophilicity. Hence, the prepared PLLA spherulites were utilized as PLLA microspheres with nanoporous surfaces for the adsorption and removal of oil in oil/water and oil-in-water emulsion. This facile method provides a novel pathway to prepare nanoporous PLLA microspheres with controllable diameters for eco-friendly oil/water and oil-in-water separation applications.

On the nature of the thermoresponsiveness of poly(2-isopropyl-2-oxazoline) in aqueous solution

Poly(2-oxazoline)s (POAs) are a class of biocompatible polymers, that is gaining a prominent role in biomedical field due to its thermoresponsiveness at temperatures compatible with physiologically relevant ones. This work represents the first extensive molecular dynamics simulation study of poly(2-isopropyl-2-oxazoline) (PiPOx) - that is amongst the simplest thermoresponsive POAs - both at infinite dilution as well as finite concentration, aimed at unveiling the thermoresponsive nature of this macromolecular class. Benchmarking simulations against experimental data obtained from specifically synthesized PiPOx's with controlled degree of polymerisation, we can explore the nature of thermoresponsive behaviour. This appears to be dominated by intermolecular interactions that lead to the experimentally observed liquid-liquid phase separation (LLPS). By means of a combined atomistic and coarse-grained approach, we could characterise the polymer rich phase formed upon LLPS, finding average properties of the solution, such as the average distance between polymer chains, that are reminiscent of the experimental lattice pitch measured on crystalline phases. At last, we can hint at the presence of a Liquid Crystalline phase in the polymer rich region at high temperatures.

Reconfigurable Reflective Colors in Holographically Patterned Liquid Crystal Gels

Thin film holographic gratings have attracted significant attention due the tailorability of their photonic properties. The ability of holography to create materials with unique photonic properties is particularly promising when combined with stimuli-responsive liquid crystals. Holographic polymer-dispersed liquid crystals (H-PDLCs) are an example of such a system where nonuniform irradiation is used to template alternating polymer-rich and polymer-poor regions with a periodicity related to the illumination wavelength. These systems typically use nonmesogenic monomers at a concentration range where a significant volume fraction of the final system is polymer. Here, we present a reconfigurable material that was generated by holographically polymer stabilizing liquid crystals (H-PSLCs) using liquid crystalline monomers, thereby enabling both alternating regions to be liquid crystalline. The “stabilizing effect” of the liquid crystalline polymer leads to a material with regions of periodic transition temperatures. As written, the polymer-rich regions have a higher isotropic transition temperature than the polymer-poor regions. Upon heating these samples beyond the isotropic temperature of the polymer-poor regions, a vivid wavelength specific reflection appears due to the refractive index mismatch between the ordered liquid crystalline polymer-rich regions and the disordered isotropic polymer-poor regions. When these materials are further heated to the isotropic temperature of the polymer-rich regions, the samples again return to a transparent state because the refractive index modulation between the alternating isotropic regions is negligible. By tailoring the liquid crystalline isotropic transition temperature to be near-room temperature, modest AC-fields can be used as an Ohmic heat source to drive the thermal color change.

Thermodynamic Modeling of Solvent-Impact on Phase Separation in Amorphous Solid Dispersions during Drying.

Understanding and prevention of unwanted changes of a pharmaceutical formulation during the production process is part of the critical requirements for the successful approval of a new drug product. Polymer-based formulations, so-called amorphous solid dispersions (ASDs), are often produced via solvent-based processes. In such processes, active pharmaceutical ingredients (APIs) and polymers are first dissolved in a solvent or solvent mixture, then the solvent is evaporated, for example, via spray drying or rotary evaporation. During the drying step, unwanted liquid-liquid phase separation may occur, leading to polymer-rich and API-rich regions with crystallization potential, and thus, heterogeneities and a two-phasic system in the final ASD. Phase separation in ASDs may impact their bioperformance because of the locally higher degree of API supersaturation. Although it is known that the choice of the solvent plays an important role in the formation of heterogeneities, solvent-impact on ASD drying and eventual product quality is often neglected in the process design. This study aims to investigate for the first time the phase behavior and drying process of API/polymer/solvents systems from a thermodynamic perspective. Unwanted phase changes during the drying process of the ASD containing hydroxypropyl methylcellulose acetate succinate and naproxen prepared from acetone/water or ethanol/water solvent mixtures were predicted using the thermodynamic model PC-SAFT. The predicted phase behavior and drying curves were successfully validated by confocal Raman spectroscopy.

Holographic polymer nanocomposites with simultaneously boosted diffraction efficiency and upconversion photoluminescence

Holographic polymer nanocomposites have drawn considerable attention due to their unique capability of reconstructing colored three-dimensional (3D) images identifiable to the naked-eye. Yet, it still remains challenging to add more and orthogonal (i.e., data access without crosstalk) optical functions to current holographic polymer nanocomposites. Herein, we design and demonstrate a holographic polymer nanocomposite with robust optical diffraction and upconversion photoluminescence. This paradigm is enabled by controlling the spatial location of upconversion nanorods (UCNRs) in the constructive (polymer-rich) regions during holographic recording, while utilizing the phase separating liquid crystal (LC) in the destructive regions to boost the refractive index difference between the constructive and destructive regions. One identical holographic image is reconstructed and readily visible to the naked-eye under ambient light, whereas four different covert luminescence states (i.e., none, blue, yellowish green and red emissions, respectively) can only be distinguishable upon the 980 nm laser illumination. The double-verifiable and crosstalk-free optical features pave a way to design new tags with orthogonal optical functions for anti-counterfeiting and security applications.

Thermoplasmonic Activated Reverse-Mode Liquid Crystal Gratings

A new generation of reconfigurable optical components is conceived by bridging the photothermal properties of gold nanoparticles and the thermosensitivity of liquid crystalline materials. As such, gold nanorods (GNRs) heated using light are used to activate efficient hidden diffraction gratings realized in a blend made of a room temperature polymerizable liquid crystal (PLC) and nematic liquid crystal (NLC). Holographic liquid crystal polymer dispersed liquid crystal (HLCPDLC) gratings containing a small percentage of GNRs are fabricated with periodicity of 2.6 μm by means of a conventional UV holographic recording setup. The HLCPDLC structures are characterized using morphological, optical, and thermooptical techniques. Because of the initial refractive index match between the polymer-rich and LC-rich regions, the “grating” is hidden and the films appear transparent and nondiffractive. Illumination of these GNR-containing structures with a suitable light source (808 nm) induces a local heating due to the...

Polymer brush relaxation during and after polymerization – Monte Carlo simulation study

The polymer chain growth in brushes takes place in a non-uniform environment which is one of the reasons of higher dispersity. Some active chain ends grow in monomer-reach regions while others in polymer-rich regions where the monomer concentration is lower. This effect depends on grafting density but also on the polymerization and diffusion rates. If chains grow fast, they adopt non-equilibrium conformations which change the polymer density profile and the growth conditions. In this paper we study this effect and chain relaxation using Monte Carlo simulation method. The growth of polymer brushes by living polymerization at various conditions was simulated until some average molecular weight was attained. Then, the polymerization was stopped and the changes of polymer parameters in time were monitored. The chain end-to-end distance increases and consequently the brush thickness increases in time. Polymer concentration decreases, especially near the grafted surface. The effect is stronger for higher polymerization rate and for higher grafting density. For low polymerization rates and lower grafting density, chain relaxation takes place during polymerization and the brush structure essentially does not change in time whenthe polymerization is finished. Such conditions assure also lower dispersity.

Relationship between the phase diagram and hysteresis in demixing and remixing for atactic and meso-rich Poly(N-isopropylacrylamide)s in water

Effects of the stereoregularity on the hysteresis in demixing and remixing of the aqueous solution of poly(N-isopropylacrylamide) (PNiPAm) observed as the dissociation of transmittance curves in heating and cooling have been studied. For the liquid-liquid phase separation of the monomer model (N-isopropyl propionamide)/water binary mixture, no hysteresis occurs in demixing and remixing when the scanning rate (vT) is small enough. On the other hand, the aqueous solution of an atactic PNiPAm with 46% of the meso content (m) shows the hysteresis even under a very dilute condition (0.01 wt%) at a slow vT of 0.01 °C min−1. The difference between demixing and remixing temperatures at vT → 0 systematically increases as m increases. The effect of stereoregularity is more significant for the cooling (remixing) process of the aqueous PNiPAm solution compared with that for the heating (demixing) process. These results strongly suggest that hysteresis arises from the structure of phase diagrams of the aqueous PNiPAm solution in which the liquid-liquid phase separation and sol-gel transition coexist [F. Tanaka et al. React. Funct. Polym. 2013, 73 (7)]. Above the demixing temperature (Tdmx), a dilute and a concentrated PNiPAm solutions appear, and the concentrated one of which solution undergoes physical gelation. The physical gel formed at the polymer-rich region returns to a sol by cooling at the remixing temperature Trmx, which lies possibly at lower than Tdmx. Thus, the hysteresis in demixing and remixing is observed.

Study of Lead Nitrate Doped PVA/PVP Blend Films using EDXRF and Complementary Techniques

Polyvinyl alcohol (PVA) − polyvinyl pyrrolidone (PVP) blend solutions were doped with different amounts of lead nitrate (Pb(NO3)2), in the doping range varying from 2.7 wt% up to 50.5 wt%. In this paper, the study of these films using Energy Dispersive X‐ray Fluorescence (EDXRF) technique in 2 π geometrical configuration is explained. In order to study K shell (Kαβ) X‐rays from the prepared films, cobalt‐57 radio‐isotope and thallium doped sodium iodide [NaI(Tl)] scintillation gamma/ x‐ray detector system with 1k MCA are used. The experiment was complemented by Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X‐ray Spectroscopy (EDS). The SEM images revealed that the filler (Pb(NO3)2) causes significant micro‐structural changes in doped PVA/PVP blend films, revealing phase separation of the material into a polymer rich region and a dopant rich region at doping levels beyond 12.1 wt%. In addition to SEM, the EDXRF study is complemented by X‐Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) scans on the Pb (NO3)2 doped PVA/PVP blend films.

Gradiently distributed iron oxide@graphene oxide nanofillers in quaternized polyvinyl alcohol composite to enhance alkaline fuel cell power density

The magnetite nanoparticles on graphene oxide (Fe3O4@GO) nanofiller are synthesized, and incorporated in a polymeric matrix to produce effective electrolyte membrane for direct alkaline methanol/ethanol fuel cells. Fe3O4@GO nanofillers (0.1%) are gradiently distributed along the through-plane direction in a quaternized poly(vinyl alcohol) (QPVA) membrane by applying an external magnetic field (MF) during the film drying step. The present study is the first work to illustrate a facile method to form gradient distribution of nanofillers in a QPVA matrix via applying MF, resulting in a polymer-rich region in the center and a nanofiller-rich region near the membrane surface. This MF assisted QPVA/0.1%Fe3O4@GO nanocomposite membrane exhibits decreased dimensional changes without sacrificing the potassium hydroxide (KOH) doping level compared to QPVA. This nanocomposite membrane design not only reduces the permeability but also improves the ionic conductivity. Maximum power densities of 200 and 144.3mWcm−2 are achieved when the fuel cell is fed with 2M methanol or 3M ethanol at 60°C using the magnetic-field assisted nanocomposite electrolyte. The fabrication of high-performance nanocomposite membrane electrolytes using a MF implies promising potential and an innovative future trend for fuel cells.

Fractographic and rheological characterizations of CF/PP-PE-copolymer composites tested in tensile

Abstract This work shows the fractographic study of fractured surfaces resulted from tensile tests of thermoplastic composites based on poly(propylene-co-ethylene) (PP-PE) and modified PP-PE copolymers reinforced with continuous carbon fibers (CF). The PP-PE matrix was modified with two agents called AM1 (based on maleic anhydride) and AM2 (containing an elastomeric agent), respectively. Three different laminates - CF/PP-PE, CF/PP-PE(AM1) and CF/PP-PE(AM2) - were manufactured. The best tensile strength and elastic modulus results were determined for the CF/PP-PE(AM1) laminate (507.6 ± 11.8 MPa and 54.7 ± 2.4 GPa, respectively). These results show that the AM1 agent contributed to increase the physicochemical interaction between the CF and the PP-PE matrix. This condition provided a better loading transfer from matrix to the reinforcement. Scanning electron microscopy analyses of the fracture surfaces show the fractographic aspects of the samples and allow evaluating the fiber/matrix-interfacial adhesion. Poor adhesion is observed for the CF/PP-PE and CF/PP-PE(AM2) laminates with the presence of fiber impressions on the polymer rich regions and fiber surfaces totally unprotected of polymer matrix. On the other side, a more consistent adhesion is observed for the CF/PP-PE(AM1) laminate. This result is in agreement with the tensile test data and show the presence of a good interaction between the laminate constituents. The correlation of the mechanical and fractographic results with the curves of complex viscosity versus temperature of the studied polymer matrices shows that the matrix viscosity did not affect the wettability of the reinforcement.

Interdiffusion of small molecules into a glassy polymer film via coarse-grained molecular dynamics simulations

The interdiffusion of the C8, the C9 and the C10 aldehyde molecules into a glassy uncrosslinked polymer film composed of four components is studied by using coarse-grained (CG) molecular dynamics simulations. Effects of the aldehyde molecule size, water and temperature on the interdiffusion processes are probed. It is found that (i) the interdiffusion generally follows the smaller-the faster rule with the smallest C8 aldehydes diffusing fastest into the polymeric film, (ii) the water molecules significantly affect the adsorption and the initial interdiffusion of the aldehyde molecules onto/into the polymer film, (iii) the interdiffusions are strongly temperature dependent as the higher temperature enhances the initial dynamics of the aldehyde-polymer systems, (iv) the computed aldehydes diffusivities are highly concentration-dependent and increase with an increase in the concentration, and (v) the aldehydes density profiles scale as t0.5 in the polymer-rich regions, and are well described by the Fickian diffusion with a constant diffusivity. Here t is the time of diffusion. Even though only relative values of the diffusivity coefficients can be predicted via the CG simulations, this work suggests that this approach is very useful in guiding the design and the selection of polymeric films with a tailored barrier property. Furthermore, it enables one to analyze small molecules-polymer interdiffusions into a polymeric film that is difficult to study experimentally but is of technological importance.

Facile microfluidic production of composite polymer core-shell microcapsules and crescent-shaped microparticles

HypothesisCore-shell microcapsules and crescent-shaped microparticles can be used as picolitre bioreactors for cell culture and microwells for cell trapping/immobilisation, respectively. ResultsMonodisperse polylactic acid (PLA) core-shell microcapsules with a diameter above 200μm, a shell thickness of 10μm, and 96% water entrapment efficiency were produced by solvent evaporation from microfluidically generated W/O/W emulsion drops with core-shell structure, and used to encapsulate Saccharomyces cerevisiae yeast cells in their aqueous cores. The morphological changes of the capsules stained with Nile red were studied over 14days under different osmotic pressure and pH gradients. FindingsThe shell retained its integrity under isotonic conditions, but buckling and particle crumbling occurred in a hypertonic solution. When the capsules containing 5wt% aqueous Eudragit® S 100 solution in the core were incubated in 10−4M HCl solution, H+ diffused through the PLA film into the core causing an ionic gelation of the inner phase and its phase separation into polymer-rich and water-rich regions, due to the transition of Eudragit from a hydrophilic to hydrophobic state. Crescent-shaped composite microparticles with Eudragit cores and PLA shells were fabricated by drying core-shell microcapsules with gelled cores, due to the collapse of PLA shells encompassing water-rich crescent regions.

Effect of Low-Concentration Polymers on Crystal Growth in Molecular Glasses: A Controlling Role for Polymer Segmental Mobility Relative to Host Dynamics.

Low-concentration polymers can strongly influence crystal growth in small-molecule glasses, a phenomenon important for improving physical stability against crystallization. We measured the velocity of crystal growth in two molecular glasses, nifedipine (NIF) and o-terphenyl (OTP), each doped with four or five different polymers. For each polymer, the concentration was fixed at 1 wt % and a wide range of molecular weights was tested. We find that a polymer additive can strongly alter the rate of crystal growth, from a 10-fold reduction to a 10-fold increase. For a given polymer, increasing molecular weight slows down crystal growth and the effect saturates around DP = 100, where DP is the degree of polymerization. For all the systems studied, the polymer effect on crystal growth rate forms a master curve in the variable (Tg,polymer - Tg,host)/Tcryst, where Tg is the glass transition temperature and Tcryst is the crystallization temperature. These results support the view that a polymer's effect on crystal growth is controlled by its segmental mobility relative to the host-molecule dynamics. In the proposed model, crystal growth rejects impurities and creates local polymer-rich regions, which must be traversed by host molecules to sustain crystal growth at rates determined by polymer segmental mobility. Our results do not support the view that host-polymer hydrogen bonding plays a controlling role in crystal growth inhibition.

Planar Phase Separation of Weak Polyelectrolyte Brushes in Poor Solvent

ABSTRACTPoly(acrylic acid) (PAA) brushes were synthesized on silicon wafer substrates using a silane linker and Z‐group RAFT method, which enables the controlled variation of brush characteristics. Atomic force microscopy (AFM) was used to characterize the brush morphology in the dry state, which ranged from isolated globules to micelles to a continuous film featuring dimples. Surface morphology was primarily determined by total grafted polymer concentration with a critical polymer concentration between 4.5 and 6.5 × 10−23mol/nm2, where the polymer rich regions transition from micellar islands to a continuous film with dimples. However, even at the highest grafting densities and brush strand lengths used in this study, a flat homogenous film was not formed. Morphological consequences of the solvent and thermal history were shown to persist into poorly solvated state after being dried. X‐ray photoelectron spectroscopy (XPS) was used to quantify the degree of remaining salt after drying. It was found that a higher relative amount of salt was retained after drying in the lower grafting density samples. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 370–377

Nanostructure of xanthan networks

Investigations of structure formation in linear and cross-linked polymer systems including one based on xanthan, an exopolysaccharide, attract theoretical and practical interest because of their widespread applications. Freeze-fracture transmission electron microscopy is used to study the structural topology formed in aqueous xanthan solutions and xanthan hydrogels. The data enable us to visualize for the first time an intact structure of xanthan formed in dilute and semidilute solutions at concentrations ranging from 0.002 to 0.5 wt %. In addition to single macromolecules, the dilute xanthan solutions are shown to contain microgels. When the concentration grows to values close to an overlap concentration (C*), a weak gel structure appears, being composed by a continuous 3D network with relatively large meshes. Macromolecular aggregation is observed in the network skeleton when switching to semidilute entangled solutions (>C**); it is accompanied by a compaction of network structure. The cross-linking of polymer chains by polyvalent Cr3+ ions gives a network skeleton composed of aggregated macromolecules at lower concentrations (around C*). Macromolecular aggregation in the skeleton of a network polymer structure occurring both in the absence and in presence of Cr3+ cations is indicative of a microphase separation into polymer-poor and polymer-rich regions.

Spinodal Decomposition of a Polymer and Ionic Liquid Mixture: Effects of Electrostatic Interactions and Hydrogen Bonds on Phase Instability

We studied the spinodal decomposition of a homopolymer and ionic liquid mixture. Our theory accounts for the dielectric contrast and hydrogen bond between the polymer and the ionic liquid and the effect of fluctuations in the local density and electrostatic potential. We attempted to rationalize the observed shift in the critical point and the asymmetry of the observed spinodal curve by applying the self-consistent field theory and Langmuir adsorption model. The dielectric contrast between the polymer and the ionic liquid produces a shift in the critical point toward polymer-rich regions. The fluctuation effect yields drastic changes in the trend of the phase boundary. We show that both effects are marked by the appearance of inflection points in the spinodal curve. Although hydrogen bonding also yields similar effects, the spinodal curve rather exhibits a double-well structure or relatively flat structure when combined with the solvation energy of ions. Hydrogen bonding, ion solvation, and the fluctuatio...

Meso-scale strain localization and failure response of an orthotropic woven glass–fiber reinforced composite

The present work focuses on studying the multi-scale deformation and failure mechanisms of an orthogonally woven glass fiber reinforced composite as a function of fiber orientation angle using digital image correlation. The full-field displacement and strain localization are effectively captured at meso-scale. At continuum scale, a remarkable change in mechanical response is observed when the loading axis diverges from principal axes. The variation in the global mechanical response is observed to be most prominent in the change of stiffness and strain at failure. At meso scale, a high degree of local deformation heterogeneity is observed and the level of inhomogeneity is found to be more prominent in case of the 45° off-axis specimens. While fiber-pull out is the major failure mode in the case of specimen loaded parallel to 0° and 90° fiber orientation, the localized shear strain developed in polymer-rich regions is the driving failure cause in the case of 45° off-axis specimen.

Effect of solvent on drug release and a spray-coated matrix of a sirolimus-eluting stent coated with poly(lactic-co-glycolic acid).

Sirolimus (SRL) release from the biodegradable poly(l-lactic-co-glycolic acid) (PLGA) matrix was investigated for the application of drug-eluting stents (DES). In particular, this study focused on whether various organic solvents affect the interaction between SRL and PLGA and the formation of microstructures during ultrasonic coating. The SRL-loaded PLGA coated by tetrahydrofuran or acetone showed a significant initial burst, whereas that from acetonitrile was constantly released during a period of 21 days. On the basis of these results, the interactions at the molecular level of SRL with the polymer matrix were estimated according to various organic solvents. Although the topographies of the coated surface were obviously different, the correlation between surface roughness and SRL release was very poor. Irrespective of organic solvents, FT-IR data showed significantly weak SRL-PLGA interactions. From the result of wide-angle X-ray diffraction, it was confirmed that SRL was dispersed in an amorphous state in the polymer matrix after ultrasonic coating. The glass-transition temperature was also influenced by organic solvents, resulting in a plasticizing effect. The particle size of SRL appeared to determine the release profile from the PLGA matrix, which was the combination of diffusion and polymer degradation at an SRL size of more than 800 nm and the Fickian release at that of less than 300 nm. Therefore, organic solvents can lead to a heterogeneous microstructure in the SRL-loaded PLGA matrix, which is at or near the surface, consisting of aggregated drug- and polymer-rich regions. It is expected that the drug release can be controlled by physicochemical properties of organic solvents, and this study can be used effectively for localized drug release in biomedical devices such as drug-eluting stents.

Anion Exchange Membranes with Tuned Ionic Conductivity

The potential of anion exchange membrane (AEM) fuel cells to provide inexpensive compact power from a wider variety of fuels than is possible with a proton exchange membrane (PEM) fuel cell, has continued to drive the research interest in this area. Alkaline catalysis in fuel cells has been demonstrated with non-precious metal catalysts, and with a variety of fuels beyond H2and methanol. Alkaline fuel cells (AFCs), based on aqueous solutions of KOH, have serious drawbacks associated with system complexity and carbonate formation. Anion exchange membrane (AEMs) fuel cells have a number of advantages over both PEM fuel cells and traditional AFCs; however, ionic conductivity in AEMs is still lower than PEMs and chemical stability of membrane attached cations in hydroxide is still not sufficient for practical applications.Our goal is to synthesize an AEM with excellent anion transport properties that can be fabricated into a thin robust film suitable for fuel cell applications. To do this with have started with polymer architectures based on homo- and co-polymers of vinylbenzyltrimethylammonium, PVBTMA, as these are readily synthesized as organized or random diblock polymers, which we can fully characterize, use for the study of anionic transport and build in-silico so that predictive modeling can be used to design next generation materials. Block copolymers that can self-assemble into well-defined hydrophobic and hydrophilic domains will better be able to achieve the stringent requirements for excellent AEM fuel cells. Membranes made from block copolymers will provide well-oriented and continuous conductive hydrophilic channels to enhance ion conductivity. Because of the presence of the hydrophobic domain in the membranes, the mechanical property of the membranes can also be enhanced. Therefore, high IEC can be achieved leading to higher conductivity. In contrast to random copolymers, it is difficult to achieve high IEC because of the associated swelling encountered at high states of hydration resulted in disintegration of the membranes. By using block copolymers containing polycation as AEMs, the relationship between structure and ionic conductivity of the membranes can be investigated as well. Several studies about structure-morphology-property relationships of block copolymers for PEM have shown that the morphology of the conductive membranes strongly influences their proton conductivity on the aspect of type and orientation of structure.We studied water partitioning in PVBTMA diblock copolymers with alternating hydrophobic lamellae (for structural support) and hydrophilic lamellae (to conduct ions). In order to be conductive, the hydrophilic block must absorb water. The water is often thought of as uniformly permeating the hydrophilic lamella, but that need not be so. Since the hydrophilic block is effectively tethered to the hydrophilic-hydrophobic interface, the polymers must stretch on average to accommodate the water. For typical well-solvated grafted layers the optimal stretching profile leads to strongly non-uniform swelling with solvent. In a simple example the polymer concentration decreases quadratically with the distance z from the tethering surface and reaches zero at a specific height h set by the solvent quality and the elastic properties of the polymer coils. Likewise for weaker solvation, there will be more polymer near the hydrophilic-hydrophobic interface, and more water at the midplane. This nonuniformity takes a special form for marginal solvation, where two concentrations exist in equilibrium. Here the tethering constraint favors the polymer-rich phase to reside near the tethering surface, while the dilute phase occupies a “water channel" near the midplane. The water configuration has potential implications for the ion conductivity of the membrane. The polymer-rich region is packed with ions (good for conductivity), but the small amount of water there inhibits ion mobility (bad for conductivity). In the water channel, this tradeoff is reversed. The consequences of this for ionic conductivity will be discussed.