Chen, Ran; Lu, Ying; Jiang, Zhiyong; Men, Yongfeng
Cavitation in Poly(4-methyl-1-pentene) during Tensile Deformation
The poly(4-methyl-1-pentene) sample was used to investigate the cavitation-induced stress-whitening phenomenon during stretching at different temperatures via the ultrasmall-angle X-ray scattering technique. Two modes of cavitation were found that mode I cavitation activated around yield point followed by mode II cavitation generated in highly oriented state. The critical strain for…
Bandgap-Tuning in Triple-Chalcogenophene Polymer Films by Thermal Annealing
González, Daniel Moseguí; Raftopoulos, Konstantinos N.; He, Gang; Papadakis, Christine M.; Brown, Alex; Rivard, Eric; Müller-Buschbaum, Peter
Macromolecular Rapid Communications, 2017, DOI:Visit the full articleBack to the overview
Blocked Shape Memory Effect in Negative Poisson’s Ratio Polymer Metamaterials
Boba, Katarzyna; Bianchi, Matteo; McCombe, Greg; Gatt, Ruben; Griffin, Anselm C.; Richardson, Robert M.; Scarpa, Fabrizio; Hamerton, Ian; Grima, Joseph N.
We describe a new class of negative Poisson’s ratio (NPR) open cell PU–PE foams produced by blocking the shape memory effect in the polymer. Contrary to classical NPR open cell thermoset and thermoplastic foams that return to their auxetic phase after reheating (and therefore limit their use in technological applications),…
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…
Progression of the Morphology in Random Ionomers Containing Bulky Ammonium Counterions
Enokida, Joshua S.; Tanna, Vijesh A.; Winter, H. Henning; Coughlin, E. Bryan
Poly(isoprene-ran-dimethyloctylammonium styrenesulfonate) (P(I-ran-DMOASS)) copolymers with high molecular weights and dimethyloctylammonium styrenesulfonate (DMOASS) compositions ranging between 8 and 40 mol % (30 and 77 wt %) were synthesized via nitroxide-mediated polymerization. Thermal and viscoelastic characterization revealed distinct behaviors for the low (30–51 wt %) and high (56–77 wt…
Effect of platelet size in a soft nanocomposite: Physical gelation and yielding
Tanna, Vijesh A.; Zhou, Yiliang; Henning Winter, H.
Journal of Rheology, 2018, vol 62, 3, pp. 791-800DOI:10.1122/1.5016535Visit the full articleBack to the overview
Studies on the 3-Lamellar Morphology of Miktoarm Terpolymers
Kim, Hyeyoung; Arras, Matthias M. L.; Mahalik, J. P.; Wang, Weiyu; Yu, Duk Man; Chernyy, Sergey; Goswami, Monojoy; Kumar, Rajeev; Sumpter, Bobby G.; Hong, Kunlun; Smith, Gregory S.; Russell, Thomas P.
The morphologies of ABC miktoarm star terpolymer consisting of polystyrene (PS), polyisoprene (PI), and poly(2-vinylpyridine) (P2VP) were studied by combining small-angle neutron and X-ray scattering (SANS and SAXS) and transmission electron microscopy. We find that this system displays a rich morphological behavior including an alternate lamellar (ALT.LAM), cylinder in undulated lamellar…
Rapid and Quantitative De-tert-butylation for Poly(acrylic acid) Block Copolymers and Influence on Relaxation of Thermoassociated Transient Networks
Filippov, Alexei D.; van Hees, Ilse A.; Fokkink, Remco; Voets, Ilja K.; Kamperman, Marleen
The synthesis of charged polymers often requires the polymerization of protected monomers, followed by a polymer-analogous reaction to the polyelectrolyte product. We present a mild, facile method to cleave tert-butyl groups from poly(tert-butyl acrylate) blocks that yields poly(acrylic acid) (pAA) blocks free of traces of the ester. The reaction utilizes…
Guided Assembly of Block Copolymers in Three-Dimensional Woodpile Scaffolds
Choi, Jaewon; Koo, Sangmo; Sakellari, Ioanna; Kim, Hyeyoung; Su, Zhengliang; Carter, Kenneth R.; Farsari, Maria; Grigoropoulos, Costas P.; Russell, Thomas P.
Three-dimensional (3D) nanofabrication using the directed self-assembly of block copolymers (BCPs) holds great promise for the nanoscale device fabrication and integration into 3D architectures over large areas with high element densities. In this work, a robust platform is developed for building 3D BCP architectures with tailored functionality using 3D micron-scale…
Size-Selective Adsorption in Nanoporous Polymers from Coumarin Photo-Cross-Linked Columnar Liquid Crystals
Concellón, Alberto; Schenning, Albertus P. H. J.; Romero, Pilar; Marcos, Mercedes; Serrano, José Luis
We have prepared nanoporous polymers from columnar hexagonal hydrogen-bonded complexes, whose order is fixed by coumarin photoinduced cycloaddition (photodimerization). Two different hydrogen-bonded complexes were used and consisted of a melamine (M) or tris(triazolyl)triazine (T) derivative acting as central templates and three peripheral carboxylic acids containing coumarin units. These…