A new family of polymer electrolytes based on a poly(allyl glycidyl ether) (PAGE) platform has been developed that overcomes many of the limitations of poly(ethylene oxide) (PEO) for battery electrolyte applications. PAGE was shown to have peak conductivities at [O]/[Li] = 16, with σ > 3 × 10 −5 S/cm at 25 °C and σ > 5 × 10 −4 S/cm at 80 °C. Below 60 °C, PAGE has a conductivity that is 10−100 times higher than that of PEO at equivalent salt concentrations with this disparity in conductivities between PAGE and PEO increasing with decreasing temperature. In addition, the synthetic versatility of allyl glycidyl ether as a building block is demonstrated by the preparation and evaluation of various AGE−EO macromolecular architectures that show superior performance to both PAGE and PEO.
We report herein the modular synthesis and nanolithographic potential of poly(dimethylsiloxane-block-methyl methacrylate) (PDMS-b-PMMA) with self-assembled domains approaching sub-10 nm periods. A straightforward and modular coupling strategy, optimized for low molecular weight diblocks and using copper-catalyzed azide–alkyne “click” cycloaddition, was employed to obtain a library of PDMS-b-PMMA and poly(dimethylsiloxane-block-styrene) (PDMS-b-PS) diblock copolymers. Flory–Huggins interaction parameters, determined from small-angle X-ray scattering experiments, were high for PDMS-b-PMMA (χ ∼ 0.2 at 150 °C), suggesting this diblock copolymer system has promise for sub-10 nm lithographic applications when compared to the corresponding PDMS-b-PS diblock copolymers (χ ∼ 0.1 at 150 °C). Performance evaluation in thin film self-assembly experiments allowed domain periods as small as 12.1 nm to be obtained, which is among the smallest highly ordered nanoscale patterns reported hitherto for thermally annealed materials.
We report a method for tuning the domain spacing ( D) of self-assembled block copolymer thin films of poly(styrene- block-methyl methacrylate) (PS- b-PMMA) over a large range of lamellar periods. By modifying the molecular weight distribution (MWD) shape (including both the breadth and skew) of the PS block via temporal control of polymer chain initiation in anionic polymerization, we observe increases of up to 41% in D for polymers with the same overall molecular weight ( M ≈ 125 kg mol) without significantly changing the overall morphology or chemical composition of the final material. In conjunction with our experimental efforts, we have utilized concepts from population statistics and least-squares analysis to develop a model for predicting D based on the first three moments of the MWDs. This statistical model reproduces experimental D values with high fidelity (with mean absolute errors of 1.2 nm or 1.8%) and provides novel physical insight into the individual and collective roles played by the MWD moments in determining this property of interest. This work demonstrates that both MWD breadth and skew have a profound influence over D, thereby providing an experimental and conceptual platform for exploiting MWD shape as a simple and modular handle for fine-tuning D in block copolymer thin films.
Grazing-incidence X-ray diffraction and rocking scans have quantified the structure of poly(3-hexylthiophene) and [6,6]-phenyl-C(61)-butyric acid methyl ester in the active layers of organic solar cells. Our study reveals that the device J(SC) correlates with the local structural development of pure PCBM and, to second order, the extent of out-of-plane P3HT π-stacking.
To control the surface properties of a polystyrene-block-poly(ethylene oxide) diblock copolymer, perfluorinated chemical moieties were specifically incorporated into the block copolymer backbone. A polystyrene-block-poly[(ethylene oxide)-stat-(allyl glycidyl ether)] [PS-b-P(EO-stat-AGE)] statistical diblock terpolymer was synthesized with varying incorporations of allyl glycidyl ether (AGE) in the poly(ethylene oxide) block from 0 to 17 mol %. The pendant alkenes of the AGE repeat units were subsequently functionalized by thiol-ene chemistry with 1H,1H,2H,2H-perfluorooctanethiol, yielding fluorocarbon-functionalized AGE (fAGE) repeat units. (1)H NMR spectroscopy and size-exclusion chromatography indicated well-defined structures with complete functionalization of the pendant alkenes. The surfaces of the polymer films were characterized after spray coating by X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS), showing that the P(EO-stat-fAGE) block starts to compete with polystyrene to populate the surface after only 1 mol % incorporation of fAGE. Increasing the incorporation of fAGE led to an increased amount of perfluorocarbons on the surface and a decrease in the concentration of PS. At a fAGE incorporation of 8 mol %, PS was not detected at the surface, as measured by NEXAFS spectroscopy. Water contact angles measured by the captive-air-bubble technique showed the underwater surfaces to be dynamic, with advancing and receding contact angles varying by >20°. Protein adsorption studies demonstrated that the fluorinated surfaces effectively prevent nonspecific binding of proteins relative to an unmodified PS-b-PEO diblock copolymer. In biological systems, settlement of spores of the green macroalga Ulva was significantly lower for the fAGE-incorporated polymers compared to the unmodified diblock and a polydimethylsiloxane elastomer standard. Furthermore, the attachment strength of sporelings (young plants) of Ulva was also reduced for the fAGE-containing polymers, affirming their potential as fouling-release coatings.
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