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Polymer Chemistry

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https://www.readbyqxmd.com/read/30546121/a-novel-soft-contact-piezo-controlled-liquid-cell-for-probing-polymer-films-under-confinement-using-synchrotron-ftir-microspectroscopy
#1
Natalie L Benbow, Jessie L Webber, Piotr Pawliszak, Damien A Sebben, Tracey T M Ho, Jitraporn Vongsvivut, Mark J Tobin, Marta Krasowska, David A Beattie
Soft polymer films, such as polyelectrolyte multilayers (PEMs), are useful coatings in materials science. The properties of PEMs often rely on the degree of hydration, and therefore the study of these films in a hydrated state is critical to allow links to be drawn between their characteristics and performance in a particular application. In this work, we detail the development of a novel soft contact cell for studying hydrated PEMs (poly(sodium 4-styrenesulfonate)/poly(allylamine hydrochloride)) using FTIR microspectroscopy...
December 13, 2018: Scientific Reports
https://www.readbyqxmd.com/read/30543257/hierarchical-modelling-of-polystyrene-melts-from-soft-blobs-to-atomistic-resolution
#2
Guojie Zhang, Anthony Chazirakis, Vagelis A Harmandaris, Torsten Stuehn, Kostas Ch Daoulas, Kurt Kremer
We demonstrate that hierarchical backmapping strategies incorporating generic blob-based models can equilibrate melts of high-molecular-weight polymers, described with chemically specific, atomistic models. The central idea is first to represent polymers by chains of large soft blobs (spheres) and efficiently equilibrate the melt on large scales. Then, the degrees of freedom of more detailed models are reinserted step by step. The procedure terminates when the atomistic description is reached. Reinsertions are feasible computationally because the fine-grained melt must be re-equilibrated only locally...
December 13, 2018: Soft Matter
https://www.readbyqxmd.com/read/30542682/feasibility-of-attenuated-total-reflection-fourier-transform-infrared-atr-ftir-chemical-imaging-and-partial-least-squares-regression-plsr-to-predict-protein-adhesion-on-polymeric-surfaces
#3
S Mukherjee, J A Martinez-Gonzalez, A A Gowen
Predicting the degree to which proteins adhere to a polymeric surface is an ongoing challenge in the scientific community to prevent non-specific protein adhesion and drive favourable protein - surface interactions. This work explores the potential of multivariate PLSR modelling in conjunction with Attenuated Total Reflection - Fourier Transform Infrared (ATR-FTIR) chemical imaging to investigate whether experimentally characterised surface chemistry can be used to predict surface protein adhesion. ATR-FTIR spectra were collected on dry and wetted polymeric surfaces, followed by evaluation of adhered fibrinogen on surfaces using the micro bicinchoninic (BCA) protein assay as a reference method...
December 13, 2018: Analyst
https://www.readbyqxmd.com/read/30540447/proton-conductive-cocrystals-of-twin-isomers-of-coordination-polymers-in-situ-formed-by-keggin-anions-and-cu-ii-4-4-bis-hydroxymethyl-2-2-bipyridine-complex-moieties
#4
Hui Yang, Xian-Ying Duan, Jia-Jia Lai, Yan Zhao, Xin-Jun Wang, Mei-Lin Wei
Cocrystals and isomers, two well-known unique concepts in supramolecular chemistry, are rarely put together until now. For the first time, we report three unprecedented and interesting cocrystals of twin isomers of coordination polymers (CPs) in situ formed by typical Keggin anions and Cu(II)-4,4'-bis(hydroxymethyl)-2,2'-bipyridine (Cu(II)-H2 L) complex moieties. In cocrystals 1-3, the Cu(II)-H2 L complex moieties are quadrisupported on Keggin-type anions through W(Mo)-Ot-Cu-Ot-W(Mo) (Ot is the terminal O atom) links in the crystal to form two twin ionic/neutral CPs with a fixed chemical stoichiometry...
December 12, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/30537686/polymer-spreading-on-substrates-with-nanoscale-grooves-using-molecular-dynamics
#5
Brooklyn A Noble, Bart Raeymaekers
Understanding how liquid polymer interacts with and spreads on surfaces with nanoscale texture features is crucial for designing complex nanoscale systems. We use molecular dynamics to simulate different types of polymer as they spread on substrates with a single nanoscale groove. We study how groove design affects the potential energy of a substrate and how this governs polymer spreading and orientation. Based on our simulations, we show that groove shape, polymer chemistry, and polymer molecule entanglement are the three parameters that determine polymer spreading on a nanoscale groove...
December 11, 2018: Nanotechnology
https://www.readbyqxmd.com/read/30534726/polyester-based-ink-platform-with-tunable-bioactivity-for-3d-printing-of-tissue-engineering-scaffolds
#6
Shen Ji, Koustubh Dube, Julian P Chesterman, Stephanie L Fung, Chya-Yan Liaw, Joachim Kohn, Murat Guvendiren
In this work, we synthesized a novel polymeric biomaterial platform with tunable functionalizability for extrusion-based 3D printing. Biodegradable polymers were synthesized using 4-hydroxyphenethyl 2-(4-hydroxyphenyl)acetate (HTy), which is derived from Tyrosol and 2-(4-hydroxyphenyl)acetic acid. p-Phenylenediacetic acid (PDA) was introduced to enhance crystallinity. To enable functionalizability without deteriorating printability, glutamic acid derivatives were introduced into the polymer design, forming copolymers including poly(HTy-co-45%PDA-co-5%Gluhexenamide ester) (HP5GH), poly(HTy-co-45%PDA-co-5%Glupentynamide ester) (HP5GP), and poly(HTy-co-45%PDA-co-5%BocGlu ester) (HP5BG)...
December 10, 2018: Biomaterials Science
https://www.readbyqxmd.com/read/30525653/precisely-self-assembly-and-controlled-catalysis-of-thermoresponsive-core-satellite-multicomponent-hybrid-nanoparticles
#7
Jia Tian, Baoxuan Huang, Weian Zhang
The construction of multicomponent hybrid nanomaterials with well-controlled architecture, especially bearing an ordered homogeneity and distribution of the subunits with tunable functions, is a key challenge in chemistry and material science. Herein, we reported a versatile and novel strategy to fabricate core-satellite multicomponent nanostructures with tunable interparticle distances and catalysis properties by the combination of surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization and self-assembly...
December 10, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/30525414/triple-function-lubricant-additives-based-on-organic-inorganic-hybrid-star-polymers-friction-reduction-wear-protection-and-viscosity-modification
#8
Bas G P van Ravensteijn, Raghida Bou Zerdan, Dongjin Seo, Nicholas A Cadirov, Takumi Watanabe, Jeffrey A Gerbec, Craig J Hawker, Jacob N Israelachvili, Matthew E Helgeson
Polymer-based lubricant additives for friction reduction, wear protection or viscosity improvement have been widely studied. However, single additives achieving all three functions are rare. To address this need, we have explored the combination of polymer topology with organic-inorganic hybrid chemistry to simultaneously vary the temperature- and shear-dependent properties of polymer additives in solution and at solid surfaces. A topological library of lubricant additives, based on statistical copolymers of stearyl methacrylate (SMA) and methyl methacrylate (MMA), ranging from linear to branched star architectures, was prepared using ruthenium-catalyzed controlled radical polymerization...
December 10, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30523988/carbon-based-polymer-nanocomposites-as-dielectric-energy-storage-materials
#9
Mohammed H Al-Saleh
Nanostructured polymeric materials based on conductive nanofillers have promising applications in the energy storage field owing to the extraordinary characteristics of the nanofillers. Conductive nanofillers, such as graphene nanoplatelets, are characterized by small size, extraordinary surface area to volume ratio, high aspect-ratio and extremely low electrical resistivity. In this work, the dielectric behaviors and the corresponding energy storage capabilities of high aspect-ratio carbon nanofiller/polymer composites were reviewed...
December 7, 2018: Nanotechnology
https://www.readbyqxmd.com/read/30523855/photocatalytic-and-antibacterial-activities-of-silver-and-iron-doped-titania-nanoparticles-in-solution-and-polyaspartic-coatings
#10
Paul A Charpentier, Chao Chen, Koosha Azhie, Bernd Grohe, Md Abdul Mumin, Adria F Lotus, Patrick Therrien, Silvia Mittler
Visible region active photocatalytic coatings are of interest for antimicrobial activity in low light applications or those employing LED lights with limited UV content. This work examined Ag and Fe doped titania nanoparticles (nTiO2) with varying dopant ranges in polyaspartic polymer coatings for potential light and dark activity. First, the Ag and Fe doped nTiO2 were synthesized by sol-gel chemistry with varying dopant concentrations, then characterized with respect to their size and aggregate size distribution, crystallinity, and surface and band gap features...
November 30, 2018: Nanotechnology
https://www.readbyqxmd.com/read/30521830/hydrogels-with-prolonged-release-of-therapeutic-antibody-block-junction-chemistry-modification-of-aba-copolymers-provides-superior-anticancer-efficacy
#11
Chuan Yang, Ashlynn Lee, Shujun Gao, Shaoqiong Liu, James L Hedrick, Yi Yan Yang
In this study, we report a new series of vitamin E-functionalized 'ABA' triblock copolymers with carbamate block junction, which can form hydrogen-bonds. These polymers were synthesized via solvent- and catalyst-free nucleophilic addition between PEG-diamine and vitamin E-functionalized cyclic carbonate. The catalyst-free synthesis enabled an easy purification step and recycling of excess monomers. The polymers formed hydrogels through self-assembly by simply dissolving in aqueous solution. The hydrogel stiffness was easily tuned by varying polymer concentration, PEG molecular weight and number of vitamin E molecules...
December 4, 2018: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/30516968/interfacial-conformation-of-hydrophilic-polyphosphoesters-affects-blood-protein-adsorption
#12
Christoph Bernhard, Kristin N Bauer, Mischa Bonn, Frederik Roman Wurm, Grazia Gonella
Synthetic polymers are commonly used as protein repelling materials for a variety of biomedical applications. Despite their widespread use, the fundamental mechanism underlying protein repellence is often elusive. Such insights are essential for improving existing, and developing new materials. Here, we investigate how subtle differences in the chemistry of hydrophilic polyphosphoesters influence the adsorption of the human blood proteins serum albumin and fibrinogen. Using thermodynamic measurements, surface-specific vibrational spectroscopy and Brewster angle microscopy, we investigate protein adsorption, hydration as well as the steric repulsion properties of the polyphosphoester polymers...
December 5, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30515896/a-novel-organic-polyurea-thin-film-for-ultralong-life-lithium-metal-anodes-via-molecular-layer-deposition
#13
Yipeng Sun, Yang Zhao, Jiwei Wang, Jianneng Liang, Changhong Wang, Qian Sun, Xiaoting Lin, Keegan R Adair, Jing Luo, Dawei Wang, Ruying Li, Mei Cai, Tsun-Kong Sham, Xueliang Sun
Metallic Li is considered as one of the most promising anode materials for next-generation batteries due to its high theoretical capacity and low electrochemical potential. However, its commercialization has been impeded by the severe safety issues associated with Li-dendrite growth. Non-uniform Li-ion flux on the Li-metal surface and the formation of unstable solid electrolyte interphase (SEI) during the Li plating/stripping process lead to the growth of dendritic and mossy Li structures that deteriorate the cycling performance and can cause short-circuits...
December 5, 2018: Advanced Materials
https://www.readbyqxmd.com/read/30512951/toward-learned-chemical-perception-of-force-field-typing-rules
#14
Camila Zanette, Caitlin Colleen Bannan, Christopher I Bayly, Josh Fass, Michael K Gilson, Michael R Shirts, John Damon Chodera, David L Mobley
Molecular mechanics force fields define how the energy and forces in a molecular system are computed from its atomic positions, thus enabling the study of such systems through computational methods like molecular dynamics and Monte Carlo simulations. Despite progress toward automated force field parameterization, considerable human expertise is required to develop or extend force fields. In particular, human input has long been required to define atom types, which encode chemically unique environments that determine which parameters will be assigned...
December 4, 2018: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/30511872/impact-of-a-single-hydrogen-substitution-by-fluorine-on-the-molecular-interaction-and-miscibility-between-sorafenib-and-polymers
#15
Chengyu Liu, Cong-Qiao Xu, Junguang Yu, Yipshu Pui, Huijun Chen, Shan Wang, Alan Donghua Zhu, Jun Li, Feng Qian
We aim to understand the potential impact of a modest chemical modification of a drug molecule on the downstream design of its amorphous solid dispersion (ASD) formulation. To this end, we used sorafenib (SOR) and its fluorinated form, regorafenib (REG), as model drugs, to assess the impact of a single hydrogen substitution by fluorine on the molecular interaction and miscibility between drug and PVP or PVP-VA, two commonly used polymers for ASDs. In this study, we observed that the Tg values of PVP or PVP-VA based SOR ASDs deviated positively from Gordon-Taylor prediction that assumes ideal mixing, yet the Tg of REG ASDs deviated negatively from or matched well with this ideal mixing model, suggesting much stronger drug-polymer interactions in SOR ASDs compared with the REG ones...
December 4, 2018: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/30511821/recent-advances-in-conjugated-tadf-polymer-featuring-in-backbone-donor-pendant-acceptor-structure-material-and-device-perspectives
#16
REVIEW
Baohua Zhang, Yanxiang Cheng
Along with the persistent research interest in organic light-emitting diode (OLED) display and lighting technology, a new studying topic is now focused on developing thermally activated delayed fluorescence (TADF) polymer emitters, with the purpose to achieve high-performance cost-effective, solution-processed OLEDs (s-OLEDs) purely from fluorescent-type materials. However, research in this topic is in its infancy about the designing rules of polymer structures, photophysical mechanisms and the correlated devices...
December 4, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/30511082/phase-behavior-of-main-chain-liquid-crystalline-polymer-networks-synthesized-by-alkyne-azide-cycloaddition-chemistry
#17
Yongjian Wang, Kelly A Burke
Liquid crystalline polymer networks (LCNs) couple polymer chain organization to molecular ordering, the switching of which has been shown to impart stimuli-responsive properties, including actuation and one-way shape memory, to the networks. While LCNs have long been proposed as artificial muscles, recent reports have also suggested potential as dynamic biomaterial substrates. In contrast to many existing LCNs synthesized using hydrophobic spacers, this work investigates networks synthesized using more hydrophilic spacers to promote interaction with water...
December 4, 2018: Soft Matter
https://www.readbyqxmd.com/read/30508515/memtein-the-fundamental-unit-of-membrane-protein-structure-and-function
#18
REVIEW
Michael Overduin, Mansoore Esmaili
The concept of a memtein as the minimal unit of membrane function is proposed here, and refers to the complex of a membrane protein together with a continuous layer of biological lipid molecules. The elucidation of the atomic resolution structures and specific interactions within memteins remains technically challenging. Nonetheless, we argue that these entities are critical endpoints for the postgenomic era, being essential units of cellular function that mediate signal transduction and trafficking. Their biological mechanisms and molecular compositions can be resolved using native nanodiscs formed by poly(styrene-co-maleic acid) (SMA) copolymers...
November 30, 2018: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/30507990/versatile-iron-catechol-based-nanoscale-coordination-polymers-with-antiretroviral-ligand-functionalization-and-their-use-as-efficient-carriers-in-hiv-aids-therapy
#19
Rubén Solórzano, Olivia Tort, Javier García-Pardo, Tuixent Escribà, Julia Lorenzo, Mireia Arnedo, Daniel Ruiz-Molina, Ramon Alibés, Félix Busqué, Fernando Novio
A novel chemical approach integrating the benefits of nanoparticles with versatility of coordination chemistry is reported herein to increase the effectiveness of well-known HIV antiretroviral drugs. The novelty of our approach is illustrated using a catechol ligand tethered to the known antiretroviral azidothymidine (AZT) as a constitutive building block of the nanoparticles. The resulting nanoscale coordination polymers (NCPs) ensure good encapsulation yields and equivalent antiretroviral activity while significantly diminishing its cytotoxicity...
December 3, 2018: Biomaterials Science
https://www.readbyqxmd.com/read/30507166/supramolecular-luminescent-sensors
#20
Teresa L Mako, Joan M Racicot, Mindy Levine
There is great need for stand-alone luminescence-based chemosensors that exemplify selectivity, sensitivity, and applicability and that overcome the challenges that arise from complex, real-world media. Discussed herein are recent developments toward these goals in the field of supramolecular luminescent chemosensors, including macrocycles, polymers, and nanomaterials. Specific focus is placed on the development of new macrocycle hosts since 2010, coupled with considerations of the underlying principles of supramolecular chemistry as well as analytes of interest and common luminophores...
December 3, 2018: Chemical Reviews
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