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Cen Lin, Erwin R Stedronsky, Luke R Jordan, Nathan J Wittenberg, Steven L Regen
A plug and socket approach for tightening polyelectrolyte multilayers is introduced based on the use pendant β-cyclodextrin groups. Prototypical multilayers derived from poly(sodium 4-styrene sulfonate) and β-cyclodextrin-containing poly(4-vinylbenzyltrimethylammonium chloride) are described. Evidence for tightened multilayers has been obtained from gas permeation, swelling and quartz crystal microbalance with dissipation (QCM-D) measurements.
August 13, 2018: Chemical Communications: Chem Comm
Victor Raul Sepulveda, Ligia Sierra, Betty Lucy López
Controlled polymerizations are often used to synthesize polymers with low dispersity, which involves expensive initiators, constrained atmospheres, and multi-step purifying processes, especially with water soluble monomers. These drawbacks make the synthesis very expensive and of little industrial value. In this report, an inexpensive free radical polymerization of sodium 4-styrenesulfonate, using benzoyl peroxide as initiator in water/ N , N -dimethylformamide solutions, is presented. After polymerization, an easy fiber precipitation method is implemented to extract and purify the polymer, obtaining conversions up to 99%, recoveries up to 98%, and molecular weight dispersities in the range of 1...
August 7, 2018: Membranes
Qian Kun Zhou, Lin Wang, Dong Liu
As a class of multifunctional materials, crystalline supramolecular complexes have attracted much attention because of their unique architectures, intriguing topologies and potential applications. In this article, a new supramolecular compound, namely catena-poly[4,4'-(buta-1,3-diene-1,4-diyl)dipyridin-1-ium [(μ4 -benzene-1,2,4,5-tetracarboxylato-κ6 O1 ,O1' :O2 :O4 ,O4' :O5 )cadmium(II)]], {(C14 H14 N2 )[Cd(C10 H2 O8 )]}n or {(1,4-H2 bpbd)[Cd(1,2,4,5-btc)]}n , has been prepared by the self-assembly of Cd(NO3 )2 ·4H2 O, benzene-1,2,4,5-tetracarboxylic acid (1,2,4,5-H4 btc) and 1,4-bis(pyridin-4-yl)buta-1,3-diene (1,4-bpbd) under hydrothermal conditions...
August 1, 2018: Acta Crystallographica. Section C, Structural Chemistry
Masaya Ito, Koki Takano, Haruka Hanochi, Yuta Asaumi, Shin-Ichi Yusa, Yoshinobu Nakamura, Syuji Fujii
Free radical dispersion polymerization was conducted to synthesize near-monodispersed, micrometer-sized polystyrene (PS) particles carrying pH-responsive poly(4-vinylpyridine) (P4VP) colloidal stabilizer (P4VP-PS particles). The P4VP-PS particles were extensively characterized in terms of morphology, size, size distribution, chemical composition, surface chemistry, and pH-response using optical and scanning electron microscopies, elemental microanalysis, X-ray photoelectron spectroscopy, laser diffraction particle size analysis, and zeta potential measurement...
2018: Frontiers in Chemistry
Thomas Stahnke, Stefan Siewert, Thomas Reske, Wolfram Schmidt, Klaus-Peter Schmitz, Niels Grabow, Rudolf F Guthoff, Andreas Wree
To prevent implant failure due to fibrosis is a major objective in glaucoma research. This study investigated the antifibrotic effects of paclitaxel (PTX), caffeic acid phenethyl ester (CAPE), and pirfenidone (PFD) coated microstent test specimens in a rat model. Test specimens based on a biodegradable blend of Poly(4-hydroxybutyrate) biopolymer and atactic Poly(3-hydroxybutyrate) were manufactured, equipped with local drug delivery (LDD) coatings, and implanted in the subcutaneous white fat depot. Postoperatively, test specimens were explanted and analyzed for residual drug content...
July 30, 2018: Bioscience Reports
Jiaxuan Ren, Xiaona Li, Tengning Ma, Bin Liu, Hao Zhang, Tao Li, Dan Lu
In this research, the effect of external fields (solvent, temperature, solution concentration and external force) on dynamic evolution from chain disorder to order of Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro- 2-[(2ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) condensed state structures was explored by UV-vis Absorption Spectra, Atomic Force Microscope (AFM) and Transmission Electron Microscopy (TEM). It was found that PTB7 main chains presented amorphous conformations induced by the poor solvent 1, 2-dichloroethane (DCE)...
July 30, 2018: ACS Applied Materials & Interfaces
Uyen Huynh, Tek Basel, Eitan Ehrenfreund, Zeev Valy Vardeny
We report transient photoinduced absorption (t-PA) and magnetic field (B) dependent t-PA (t-MPA(B)) in a pristine low bandgap π-conjugated copolymer composed of donor and acceptor moieties, namely the poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thi-eno[3,4-b]thiophenediyl]]) ( or PTB7) used in photovoltaic applications. Unlike traditional π-conjugated polymers in which the primary photoexcitations are singlet excitons (SE), in pristine PTB7 we find at short times coexistence of two primary photoexcitation species, namely SE and triplet-triplet (TT) pair...
July 27, 2018: Journal of Physical Chemistry Letters
Valeria Villalobos, Angel Leiva, Hernan E Ríos, Jorge Enrique Pavez, Carlos Silva, Mohammed Ahmar, Yves Queneau, Jenny M Blamey, Francisco P Chávez, Marcela D Urzúa
Inhibiting pathogenic bacterial adherence on surfaces is an ongoing challenge to prevent the development of biofilms. Multilayer polyelectrolyte films are feasible antibacterial materials. Here we have designed new films made of carbohydrate polyelectrolytes to obtain antibacterial coatings that prevent biofilm formation. The polyelectrolyte films were constructed from poly(maleic anhydride-alt-styrene) functionalized with glucofuranose derivatives and quaternized poly(4-vinylpyridine) N-alkyl. These films prevent Pseudomonas aeruginosa and Salmonella Typhimurium, two important bacterial contaminants in clinical environments, from adhering to surfaces...
July 23, 2018: ACS Applied Materials & Interfaces
Zahra Mehrani, Homeira Ebrahimzadeh, Ali Reza Aliakbar, Ali Akbar Asgharinezhad
4-Nitroaniline was electropolymerized in a weakly alkaline medium, and the resulting poly(4-nitroaniline) (P4-NA)) was used to fabricate - by electrospinning - a nanofiber consisting of P4-NA and poly(vinyl alcohol) (PVA). The PVA fraction was then dissolved in hot water and this causes the porosity of electrospun nanofiber to be largely enhanced. The resulting nanofiber was utilized as a sorbent for solid phase microextraction of the model organophosphorus pesticides diazinon and chloropyrifos from aqueous media...
July 21, 2018: Mikrochimica Acta
Havid Aqoma, Sujung Park, Hye-Yun Park, Wisnu Tantyo Hadmojo, Seung-Hwan Oh, Sungho Nho, Do Hui Kim, Jeonghoon Seo, Sungmin Park, Du Yeol Ryu, Shinuk Cho, Sung-Yeon Jang
The enhancement of interfacial charge collection efficiency using buffer layers is a cost-effective way to improve the performance of organic photovoltaic devices (OPVs) because they are often universally applicable regardless of the active materials. However, the availability of high-performance buffer materials, which are solution-processable at low temperature, are limited and they often require burdensome additional surface modifications. Herein, high-performance ZnO based electron transporting layers (ETLs) for OPVs are developed with a novel g -ray-assisted solution process...
July 2018: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Kuen-Wei Tsai, Yun-Chung Wu, Tzu-Hao Jen, Show-An Chen
Conjugated polyelectrolytes and their precursors as electron-injection layer (EIL) in polymer light-emitting diode have attracted extensive attention because they allow the use of environmentally stable high work function metals as cathode with efficient electron injection. Here, for the first time, we find that an undesirable green emission component (470-650 nm) in the electroluminescence spectra is observed during continuous operation of deep-blue emission β-phase poly(9,9-dioctyl-2,7-fluorene) (β-PFO) device upon introducing polyelectrolyte poly[9,9-bis(6'-(18-crown-6)methoxy)hexyl fluorene] chelating to potassium ion (PFCn6:K+ ) as EIL...
August 8, 2018: ACS Applied Materials & Interfaces
Vanessa Gómez-Vallejo, María Puigivila, Sandra Plaza-García, Boguslaw Szczupak, Rafael Piñol, José L Murillo, Victor Sorribas, Gustavo Lou, Sabino Veintemillas, Pedro Ramos-Cabrer, Jordi Llop, Angel Millán
In vitro experiments have shown the great potential of magnetic nanocarriers for multimodal imaging diagnosis and non-invasive therapies. However, their extensive clinical application is still jeopardized by a fast retention in the reticuloendothelial system (RES). The other issue that restrains their potential performance is slow degradation and excretion, which increases their risks of toxicity. We report a promising case in which multicore iron oxide nanoparticles coated with a poly(4-vinylpyridine) polyethylene glycol copolymer show low RES retention and high urinary excretion, as confirmed by single photon emission computerized tomography (SPECT), gamma counting, magnetic resonance imaging (MRI) and electron microscopy (EM) biodistribution studies...
August 7, 2018: Nanoscale
Marta Tsirigotis-Maniecka, Lilianna Szyk-Warszyńska, Aneta Michna, Piotr Warszyński, Kazimiera A Wilk
This work reports the development of different types of alginate hydrogel microparticles designed specifically for the esculin (ESC) payload. Negatively charged alginate (ALG) microspheres were prepared by the ionotropic gelation technique, and an oppositely charged polyelectrolyte (PE) shell as a compatible polycation (chitosan (CHIT) or gelatin (GEL)) or a synthetic PEs (poly(allylamine hydrochloride) (PAH) and poly(4-styrenesulfonate) (PSS)) were adsorbed using electrostatic complexation. Thorough characterization of microparticles was performed with advanced microscopic techniques (scanning electron, fluorescence and confocal), followed by stability studies, ESC encapsulation efficacy determination and in vitro release kinetics measurements...
July 3, 2018: Journal of Colloid and Interface Science
Dong-Jin Yun, Changhoon Jung, Sunjung Byun, Hyemin Ra, Jung-Min Kim, Seunghyup Lee, Jinyoung Hwang, Sung-Hoon Park
In this study, composite films made of coiled carbon nanotubes (CCNTs) and poly(3,4-ethylenedioxythiophene) polymerized with poly(4-styrenesulfonate) (PEDOT:PSS) were fabricated with different composition ratios. The variations in film properties (including surface morphology, work function, and electrical conductivity) in accordance with the amount of CCNT dosing were investigated. Subsequently, through HCl-methanol treatment, we achieved a significant enhancement in electrical conductivity with little damage to the CCNT features...
September 28, 2018: Nanotechnology
Sora Oh, Da Hun Kim, Taek Ahn, Sang Kyu Lee
A novel series of benzodithiophene-4,8-dione (BDD)-based copolymers, poly[(4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indacenodithiophene-2,7-diyl)-alt-(1,3-bis(2-ethylhexyl)-5,7-di(thiophene2-yl)benzodithiophene-4,8-dione)] (P1) and poly[(5,5,11,11-tetrakis(4-hexylphenyl)dithieno[2,3-d: 2',3'-d']-s-indacenodithiophene-3,9-diyl)-alt-(1,3-bis(2-ethylhexyl)-5,7-di(thiophene-2-yl)benzodithiophene-4,8-dione)] (P2), which have the same acceptor moiety but different donor segments, have been designed and synthesized for use as donor materials in solution-processable polymer solar cells (PSCs)...
October 1, 2018: Journal of Nanoscience and Nanotechnology
Eleanor E McCabe-Lankford, Theodore L Brown, Nicole H Levi-Polyachenko
OBJECTIVE: Photothermal therapy (PTT) uses light absorbing materials to generate heat for treatment of diseases, like cancer. The advantages of using PTT components that absorb in the near-infrared (NIR) include reduced tissue auto-fluorescence and higher penetration depths. However, NIR laser light can still be scattered and absorbed by biological tissues, thus decreasing the amount of the energy reaching the PTT agents. We have developed two distinct formulations of NIR-absorbing nanoparticles, one which can be utilized for PTT only, and another for both PTT and fluorescence imaging of colorectal cancer...
June 28, 2018: Lasers in Surgery and Medicine
Ahmed Owais, Truis Smith-Palmer, Angus Gentle, Chiara Neto
Underwater superoleophobic surfaces can be considered a particular type of lubricant-infused surface, that have anti-fouling properties by virtue of a trapped water layer that repels oils. However, as their function relies on a water layer being trapped in the surface roughness, it is crucial to understand the factors that determine the layer stability. In this work, the forces that are responsible for the stability of thin liquid films within structured surfaces were quantified, and the conclusions were tested against the performance of wrinkled surfaces as underwater superoleophobic coatings...
June 26, 2018: Soft Matter
Linxi Zhang, Yingjie Yu, Kuan-Che Feng, Ya-Chen Chuang, Xianghao Zuo, Yuchen Zhou, Chung-Cheuh Chang, Marcia Simon, Miriam Rafailovich
Eventhough it is well established that materials can promote stem cell differentiation, hard tissue formation is a templated process for which little is known regarding the in vitro process. We have found that surface curvature enables self-assembly of triple helical collagen fibrils into banded bundle structures from rat tail and human collagen secreted by dental pulp stem cells. Collagen fibrils were adsorbed at 4 °C on spun cast flat P4VP films and electrospun fibers. Protein adsorption was observed on both surfaces, but large banded bundles with a uniform spacing of approximately 55 nm were present only on the fiber surfaces...
June 22, 2018: Acta Biomaterialia
Hyunjin Park, Jimin Kwon, Boseok Kang, Woojo Kim, Yun-Hi Kim, Kilwon Cho, Sungjune Jung
Poly(4-vinylphenol) (PVP) is a promising gate dielectric material for organic field-effect transistors (OFETs) and circuits fabricated on plastic substrates. Thermal cross-linking of PVP with a cross-linker, such as poly(melamine- co-formaldehyde) methylated (PMF), at a high temperature (above 170 °C) is widely considered an effective method to remove residual hydroxyl groups that induce polarization effects in the dielectric bulk. However, the threshold voltage shift in transfer characteristics is still observed for an OFET with a PVP-PMF dielectric when it is operated at a slow gate voltage sweep rate...
July 18, 2018: ACS Applied Materials & Interfaces
Enrico Miceli, Stefanie Wedepohl, Ernesto Rafael Osorio Blanco, Guido Noé Rimondino, Marisa Martinelli, Miriam Strumia, Maria Molina, Mrityunjoy Kar, Marcelo Calderón
The use of thermoresponsive nanogels (NGs) allows the controlled release of therapeutic molecules upon a thermal switch. Usually, this strategy involves the use of temperature increase to activate cargo expulsion from shrinking NGs. In this study, poly(N-isopropylacrylamide) (pNIPAM)-based NGs were involved in the release of a therapeutic protein corona by temperature decrease. NGs based on dendritic polyglycerol (dPG) and thermoresponsive pNIPAM were semi-interpenetrated with poly(4-acryloylamine-4-(carboxyethyl)heptanodioic acid) (pABC)...
June 19, 2018: European Journal of Pharmaceutics and Biopharmaceutics
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