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Polymer Chemistry

Jialin Mao, Wei Zhang, Stephen Zd Cheng, Chrys Wesdemiotis
Monodisperse, sequence-defined polymers can be potentially used for digital data storage. This study reports the sequence analysis and differentiation of monodisperse polyester copolymers carrying side chains functionalized in a specific order by polyhedral oligomeric silsesquioxane (POSS) nanoparticles. Steglich esterification and succinic anhydride ring-opening chemistries were utilized iteratively to synthesize the intended sequences, which were characterized by matrix-assisted laser desorption ionization tandem mass spectrometry (MALDI-MS2 )...
February 2019: European Journal of Mass Spectrometry
Hanjun Hao, Mengmeng Sun, Pengyong Li, Jiawei Sun, Xinyu Liu, Weiping Gao
Hydrogen peroxide (H2O2)-generating enzymes (HGEs) are potentially useful for tumor therapy, but the potential is limited by the challenge in regulating H2O2 production. Herein we present site-specific in situ growth (SIG) of a cationic polymer of poly (N, N'-dimethylamino-2-ethyl methacrylate) (PDMA) from the N-terminus of glucose oxidase (GOX) to generate a site-specific and cationic GOX-PDMA conjugate with well retained activity and enhanced stability to regulate H2O2 generation for cancer starvation and H2O2 therapy...
February 18, 2019: ACS Applied Materials & Interfaces
Frederik Kotz, Patrick Risch, Dorothea Helmer, Bastian E Rapp
3D printing has emerged as an enabling technology for miniaturization. High-precision printing techniques such as stereolithography are capable of printing microreactors and lab-on-a-chip devices for efficient parallelization of biological and biochemical reactions under reduced uptake of reactants. In the world of chemistry, however, up until now, miniaturization has played a minor role. The chemical and thermal stability of regular 3D printing resins is insufficient for sustaining the harsh conditions of chemical reactions...
February 18, 2019: Advanced Materials
Devaraj Bharathi, R Ranjithkumar, B Chandarshekar, V Bhuvaneshwari
The surface coating of metal oxide nanoparticles using biopolymer chitosan has evolved to become an important area of polymer nanotechnology. Herein, we report the preparation of chitosan coated zinc oxide (CS-ZnO) nanocomposite for the first time by a green chemistry approach using bioflavonoid rutin. The formation of CS-ZnO nanocomposite was preliminarily confirmed by color change and UV-Visible spectroscopy. FE-SEM images revealed agglomeration of CS-ZnO nanocomposite having predominant rod shaped structure...
February 13, 2019: International Journal of Biological Macromolecules
Lindani Mdlalose, Mohammed Balogun, Maris Klavins, Christopher Deeks, Jon Treacy, Luke Chimuka, Avashnee Chetty
Water pollution due to industrial processes has necessitated and spurred robust research into the development of adsorbent materials for remediation. Polyphenylenediamines (PPD) have attracted significant attention because of their dual cationic and redox properties. They are able to reduce Cr(VI) to Cr(III) in solution. Interrogation of the chemical processes involved in the Cr(VI) adsorption on para-PPD was primarily by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy...
December 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Saravanan Kasipandi, Jong Wook Bae
Value-added aromatic monomers such as benzene, toluene, and xylenes (BTX) are very important building-block chemicals for the production of plastics, polymers, solvents, pesticides, dyes, and adhesives. Syngas-to-aromatics (STA) is a very promising approach for the synthesis of aromatic monomers, and is catalyzed via bifunctional catalysts in a single reactor, wherein methanol/dimethyl ether and/or olefins intermediates formed from syngas on metal components are converted into aromatic monomers exclusively on the HZSM-5 by cascade reactions...
February 15, 2019: Advanced Materials
Yong Hu, Christof M Niemeyer
In the past 35 years, DNA nanotechnology has grown to a highly innovative and vibrant field of research at the interface of chemistry, materials science, biotechnology, and nanotechnology. Herein, a short summary of the state of research in various subdisciplines of DNA nanotechnology, ranging from pure "structural DNA nanotechnology" over protein-DNA assemblies, nanoparticle-based DNA materials, and DNA polymers to DNA surface technology is given. The survey shows that these subdisciplines are growing ever closer together and suggests that this integration is essential in order to initiate the next phase of development...
February 15, 2019: Advanced Materials
Kunal Karan
Ion-containing perfluorinated polymers possess unique viscoelastic properties, excellent proton conductivity, and nano-phase-segregated structure all arising from the clustering of hydrophilic sulphonic acid groups within a matrix of hydrophobic fluorocarbons. When these ionomers are confined to nanothin films, a broad swathe of structural organization imparting a rich variety of surface, interfacial and bulk characteristics can be expected. However, our understanding of perfluorinated ionomer thin film behavior is still in a rudimentary stage with much of the focus on the hydration-related structure/properties pertinent to electrochemical applications...
February 12, 2019: Langmuir: the ACS Journal of Surfaces and Colloids
Benjamin Cressiot, Hadjer Ouldali, Manuela Pastoriza-Gallego, Laurent Bacri, F Gisou van der Goot, Juan Pelta
Nanopore electrical approach is a breakthrough in single molecular level detection of particles as small as ions, and complex as biomolecules. This technique can be used for molecule analysis, and characterization as well as for the understanding of confined medium dynamics in chemical or biological reactions. Altogether, the information obtained from these kinds of experiments will allow to address challenges in a variety of biological fields. The sensing, design and manufacture of nanopores is crucial to obtain these objectives...
February 12, 2019: ACS Sensors
Audrey R Sulkanen, Jaeuk Sung, Maxwell J Robb, Jeffrey S Moore, Nancy R Sottos, Gang-Yu Liu
Mechanically sensitive molecules known as mechanophores have recently attracted much interest due to the need for mechanoresponsive materials. Maleimide-anthracene mechanophores located at the interface between poly(glycidyl methacrylate) (PGMA) polymer brushes and Si wafer surfaces were activated locally using atomic force microscopy (AFM) probes to deliver mechanical stimulation. Each individual maleimide-anthracene mechanophore exhibits binary behavior: undergoing a retro [4+2] cycloaddition reaction under high load to form a surface-bound anthracene moiety and free PGMA, or remaining unchanged if the load falls below the activation threshold...
February 12, 2019: Journal of the American Chemical Society
Yoshinobu Mato, Kohei Honda, Kenji Tajima, Takuya Yamamoto, Takuya Isono, Toshifumi Satoh
Cage-shaped polymers, or "macromolecular cages", are of great interest as the macromolecular analogues of molecular cages because of their various potential applications in supramolecular chemistry and materials science. However, the systematic synthesis of macromolecular cages remains a great challenge. Herein, we describe a robust and versatile synthetic strategy for macromolecular cages with defined arm numbers and sizes based on the intramolecular consecutive cyclization of highly reactive norbornene groups attached to each end of the arms of a star-shaped polymer precursor...
January 14, 2019: Chemical Science
Gustav Ferrand-Drake Del Castillo, Meike König, Martin Müller, Klaus-Jochen Eichhorn, Manfred Stamm, Petra Uhlmann, Andreas B Dahlin
Catalysis by enzymes on surfaces has many applications. However, strategies for efficient enzyme immobilization with preserved activity are still in need of further development. In this work we investigate polyelectrolyte brushes prepared by both grafting-to and grafting-from with the aim to achieve high catalytic activity. For comparison, self-assembled monolayers that bind enzymes with the same chemical interactions are included. We use the model enzyme glucose oxidase and two kinds of polymers: anionic poly(acrylic acid) and cationic poly(diethylamino)methyl methacrylate...
February 11, 2019: Langmuir: the ACS Journal of Surfaces and Colloids
Eunjung Kim, Shweta Agarwal, Nayoung Kim, Fredrik Sydow Hage, Vincent Leonardo, Amy Gelmi, Molly M Stevens
Nucleic acid nanostructures have attracted significant interest as potential therapeutic and diagnostic platforms due to their intrinsic biocompatibility and biodegradability, structural and functional diversity, and compatibility with various chemistries for modification and stabilization. Among the fabrication approaches for such structures, the rolling circle techniques have emerged as particularly promising, producing morphologically round, flower-shaped nucleic acid particles: typically hybrid composites of long nucleic acid strands and inorganic magnesium pyrophosphate (Mg2 PPi)...
February 11, 2019: ACS Nano
Nongnoot Wongkaew, Marcel Simsek, Palaniappan Arumugam, Arne Behrent, Sheela Berchmans, Antje J Baeumner
3D-porous carbon nanomaterials and their hybrids are ideal materials for energy storage and conversion, biomedical research, and wearable sensors, yet today's fabrication methods are too complicated and inefficient to implement into miniaturized systems. Instead, it is shown here that 3D-carbon nanofibrous electrodes of various designs, shapes and sizes, on flexible substrates, under ambient conditions and without complicated equipment and procedures can simply be "written" via a one-step laser-induced carbonization on electrospun nanofibers...
February 11, 2019: Nanoscale
Sylvain Grosjean, Mirella Wawryszyn, Hatice Mutlu, Stefan Bräse, Joerg Lahann, Patrick Theato
Bioinspiration has emerged as an important design principle in the rapidly growing field of materials science and especially its subarea, soft matter science. For example, biological cells form hierarchically organized tissues that not only are optimized and designed for durability, but also have to adapt to their external environment, undergo self-repair, and perform many highly complex functions. Being able to create artificial soft materials that mimic those highly complex functions will enable future materials applications...
February 10, 2019: Advanced Materials
Mohammad Atif Faiz Afzal, Johannes Hachmann
In a previous study, we introduced a new computational protocol to accurately predict the index of refraction (RI) of organic polymers using a combination of first-principles and data modeling. This protocol is based on the Lorentz-Lorenz equation and involves the calculation of static polarizabilities and number densities of oligomer sequences, which are extrapolated to the polymer limit. We chose to compute the polarizabilities within the density functional theory (DFT) framework using the PBE0/def2-TZVP-D3 model chemistry...
February 8, 2019: Physical Chemistry Chemical Physics: PCCP
Xiaofeng Wu, Jessica A Smith, Samuel Petcher, Bowen Zhang, Douglas J Parker, John M Griffin, Tom Hasell
The discovery of inverse vulcanization has allowed stable polymers to be made from elemental sulfur, an unwanted by-product of the petrochemicals industry. However, further development of both the chemistry and applications is handicapped by the restricted choice of cross-linkers and the elevated temperatures required for polymerisation. Here we report the catalysis of inverse vulcanization reactions. This catalytic method is effective for a wide range of crosslinkers reduces the required reaction temperature and reaction time, prevents harmful H2 S production, increases yield, improves properties, and allows crosslinkers that would be otherwise unreactive to be used...
February 7, 2019: Nature Communications
Husain N Kagalwala, Noémie Lalaoui, Qian-Li Li, Liang Liu, Toby Woods, Thomas B Rauchfuss
The chemistry of Fe2 (μ-SH)2 (CO)4 (PPh3 )2 (2HH ) is described with attention to S-S coupling reactions. Produced by the reduction of Fe2 (μ-S2 )(CO)4 (PPh3 )2 (2), 2HH is an analogue of Fe2 (μ-SH)2 (CO)6 (1HH ), which exhibits well-behaved S-centered redox. Both 2HH and the related 2MeH exist as isomers that differ with respect to the stereochemistry of the μ-SR ligands (R = H, Me). Compounds 2HH , 2MeH , and 2 protonate to give rare examples of Fe-SH and Fe-S2 hydrides. Salts of [H2]+ , [H2HH ]+ , and [H2MeH ]+ were characterized crystallographically...
February 6, 2019: Inorganic Chemistry
Emily L Kynaston, K J Winchell, Patrick Y Yee, Joseph G Manion, Arthur D Hendsbee, Yuning Li, Sven Huettner, Sarah H Tolbert, Dwight S Seferos
Understanding self-assembly behavior and resulting morphologies in block co-polymer films is an essential aspect of chemistry and materials science. Although the self-assembly of amorphous coil-coil block co-polymers is relatively well understood, that of semicrystalline block co-polymers where each block has distinct crystallization properties remains unclear. Here, we report a detailed study to elucidate the rich self-assembly behavior of conjugated thiophene-selenophene (P3AT- b-P3AS) block co-polymers. Using a combination of microscopy and synchrotron-based X-ray techniques, we show that three different film morphologies, denoted as lamellae, co-crystallized fibers, and patchy fibers, arise from the self-assembly of these block co-polymers over a relatively narrow range of overall degrees of polymerization (30 < N < 90)...
February 5, 2019: ACS Applied Materials & Interfaces
Marcin Dabrowski, Agnieszka Ziminska, Jakub Kalecki, Maciej Cieplak, Wojciech Lisowski, Radoslaw Maksym, Shuai Shao, Francis D'Souza, Alexander Kuhn, Piyush Sindhu Sharma
We present an improved approach for the preparation of highly selective and homogeneous molecular cavities in molecularly imprinted polymers (MIP) via the combination of surface imprinting and semi-covalent imprinting. Towards that, first a colloidal crystal mold was prepared via the Langmuir-Blodgett technique. Then, human chorionic gonadotropin (hCG) template protein was immobilized on the colloidal crystal mold. Later, hCG derivatization with electroactive functional monomers via amide chemistry was performed...
February 4, 2019: ACS Applied Materials & Interfaces
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