Kim, Hyeyoung; Kang, Beom-Goo; Choi, Jaewon; Sun, Zhiwei; Yu, Duk Man; Mays, Jimmy; Russell, Thomas P.
Morphological Behavior of A2B Block Copolymers in Thin Films
Copolymer composed of two poly(2-vinylpyridine) blocks and one polystyrene block ((P2VP)2–PS) with a PS volume fraction (ΦPS) of 0.44 was synthesized, and their morphologies in bulk and thin films were compared to linear block copolymers (BCPs) having a similar ΦPS (PS-b-P2VP). For the symmetric diblock copolymer, a lamellar morphology was…
Designing Block Copolymer Architectures toward Tough Bioplastics from Natural Rosin
Rahman, Md Anisur; Lokupitiya, Hasala N.; Ganewatta, Mitra S.; Yuan, Liang; Stefik, Morgan; Tang, Chuanbing
Resin acids (or natural rosin) are a class of abundant, renewable natural biomass. Most low molecular weight resin acid-containing polymers are very brittle due to their low chain entanglement associated with the pendant, intrinsically bulky hydrophenanthrene group. The use of block copolymer architectures can enhance chain entanglement and thus improve…
Adjuvants Based on Synthetic Mycobacterial Cord Factor Analogues: Biophysical Properties of Neat Glycolipids and Nanoself-Assemblies with DDA
Kallerup, Rie S.; Franzyk, Henrik; Schiøth, Mikkel L.; Justesen, Sarah; Martin-Bertelsen, Birte; Rose, Fabrice; Madsen, Cecilie M.; Christensen, Dennis; Korsholm, Karen S.; Yaghmur, Anan; Foged, Camilla
Synthetic mycobacterial cord factor analogues, e.g., trehalose 6,6′-dibehenate (TDB), are highly promising adjuvants due to their strong immunopotentiating capabilities, but their biophysical properties have remained poorly characterized. Here, we report the synthesis of an array of synthetic TDB analogues varying in acyl chain length, degree of acylation, and headgroup display,…
Characterization of cereal β-glucan extracts: Conformation and structural aspects
Zielke, Claudia; Stradner, Anna; Nilsson, Lars
Several health benefits have been established for cereal mixed-linkage β-glucan of high molar mass (M), and are said to be attributed to the ability of β-glucan to form viscous slurries in the gut. As no comprehensive understanding exists yet, the characterization of β-glucan solution behavior is crucial. β-Glucan was characterized…
Evaluation of the Interaction Parameter for Poly(solketal methacrylate)-block-polystyrene Copolymers
Yu, Duk Man; Mapas, Jose Kenneth D.; Kim, Hyeyoung; Choi, Jaewon; Ribbe, Alexander E.; Rzayev, Javid; Russell, Thomas P.
A series of symmetric poly(solketal methacrylate-b-styrene) (PSM-b-PS) copolymers with varying molecular weights that can transform a hydrophobic PSM block to a hydrophilic poly(glycerol monomethacrylate) (PGM) block through an acid hydrolysis were investigated. This simple chemical transformation significantly enhances the segmental interaction parameter (χ), enabling a phase-mixed block…
Changes in Nafion® 117 internal structure and related properties during exposure to elevated temperature and pressure in an aqueous environment
Mališ, Jakub; Paidar, Martin; Bystron, Tomas; Brožová, Libuše; Zhigunov, Alexander; Bouzek, Karel
In this study the behaviour and structure of a Nafion® 117 membrane exposed to liquid water at temperatures and pressures of up to 150 °C and 700 kPa, respectively, were investigated. The results clearly showed that, as the temperature of the environment approaches or exceeds the glass transition temperature of the membrane,…
Polymer-Grafted Nanoparticle Membranes with Controllable Free Volume
Bilchak, Connor R.; Buenning, Eileen; Asai, Makoto; Zhang, Kai; Durning, Christopher J.; Kumar, Sanat K.; Huang, Yucheng; Benicewicz, Brian C.; Gidley, David W.; Cheng, Shiwang; Sokolov, Alexei P.; Minelli, Matteo; Doghieri, Ferruccio
Polymer-based membranes play a key role in several industrially important gas separation technologies, e.g., removing CO2 from natural gas, with enormous economic and environmental impact. Here, we develop a novel hybrid membrane construct comprised entirely of nanoparticles grafted with polymers. These membranes are shown to have broadly tunable separation performance…
Polystyrene-block-poly(ethylene oxide) Bottlebrush Block Copolymer Morphology Transitions: Influence of Side Chain Length and Volume Fraction
Gai, Yue; Song, Dong-Po; Yavitt, Benjamin M.; Watkins, James J.
A systematic study was conducted to investigate the morphology transitions that occur in polystyrene-block-poly(ethylene oxide) (PS-b-PEO) bottlebrush block copolymers (BBCP) upon varying PEO volume fraction (fPEO) from 22% to 81%. A series of PS-b-PEO BBCPs with different PEO side chain lengths were prepared using ring-opening metathesis polymerization (ROMP) of PEO–norbornene…
Molecular Alignment in Polyethylene during Cold Drawing Using In-Situ SANS and Raman Spectroscopy
López-Barrón, Carlos R.; Zeng, Yiming; Schaefer, Jonathan J.; Eberle, Aaron P. R.; Lodge, Timothy P.; Bates, Frank S.
Changes in the crystalline and mesoscale lamellar structure during plastic deformation of semicrystalline polymers have been extensively studied by X-ray diffraction techniques. However, direct measurements of single chain conformations during stretching have not been realized, although they are key to fully understand the structural transitions during cold drawing and their…
Poly(arylene piperidinium) Hydroxide Ion Exchange Membranes: Synthesis, Alkaline Stability, and Conductivity
Olsson, Joel S.; Pham, Thanh Huong; Jannasch, Patric
A series of poly(arylene piperidinium)s (PAPipQs) devoid of any alkali-sensitive aryl ether bonds or benzylic sites are prepared and studied as anion exchange membranes (AEMs) for alkaline fuel cells. First, the excellent alkaline stability of the model compound 4,4-diarylpiperidinium is confirmed. Medium molecular weight poly(arylene piperidine)s are then synthesized in…