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https://www.readbyqxmd.com/read/30507203/kinetically-controlled-self-assembly-of-block-copolymers-into-segmented-worm-like-micelles-in-microfluidic-chips
#1
Zhengping Tan, Wei Lan, Qianqian Liu, Ke Wang, Mubashir Hussain, Min Ren, Zhen Geng, Lianbin Zhang, Xiaobing Luo, Lixiong Zhang, Jintao Zhu
Kinetically controlled self-assembly of block copolymers (BCPs) in solution is an efficient route to fabricate complex hierarchical colloids which are of great importance for nanoencapsulation, microreactors, and biomimics. Herein, segmented worm-like micelles (SWMs) with controllable size are generated by self-assembly of polystyrene-block-poly(4-vinyl pyridine) (PS-b-P4VP) in microfluidic channel. Different from the assembly of BCPs off-chip at the same solution properties, it is found that the fabricated SWMs are kinetically controlled assemblies with thermodynamic metastable structures, which are formed by orderly aggregation of preformed spherical micelles due to fast mixing process in microfluidic channels...
December 3, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/30472622/immobilization-of-functional-polymers-on-poly-4-benzoyl-pxylylene-co-p-xylylene-films-via-photochemical-conjugation-for-modulation-of-cell-adhesion
#2
Ibrahim Nasser Ahmed, Ray Chang, Ming-Chun Keng, Hsiu-Wen Chien, Hsien-Yeh Chen, Wei-Bor Tsai
Surface modification with functional materials, such as anti-fouling or thermal responsive polymers, on biomedical devices benefits their clinical performance. Simple and versatile technologies, which could be applied to a wide variety of substrates, are still highly desirable. Chemical vapor deposition (CVD) of 4-benzoyl-[2,2]paracyclophane (Benzoyl-PPX) layers attracts much attention because the photoreactive platform could be deposited onto almost every substrate for the conjugation of functional molecules...
November 11, 2018: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/30456944/antifouling-ion-exchange-resins
#3
Yara E Ghoussoub, Hadi M Fares, Jose D Delgado, Laura R Keller, Joseph B Schlenoff
Large quantities of organic ion-exchange resins are used worldwide for water decontamination and polishing. Fouling by microorganisms and decomposition products of natural organic matter severely limits the lifetime of these resins. Much research has thus been invested in polymer-based antifouling coatings. In the present study, poly(4-styrenesulfonate) (PSS) and a co-polymer of PSS and a zwitterionic group were used to spontaneously coat commercial Dowex 1X8 anion-exchange resin. UV-visible spectroscopy provided a precise measure of the kinetics and amount of PSS sorbed onto or into resin beads...
November 20, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30446111/a-comparative-study-on-grafting-polymers-from-cellulose-nanocrystals-via-surface-initiated-atom-transfer-radical-polymerization-atrp-and-activator-re-generated-by-electron-transfer-atrp
#4
Zhen Zhang, Xiaosong Wang, Kam C Tam, Gilles Sèbe
Both Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) and Surface-Initiated Activator Re-Generated by Electron Transfer ATRP (SI-ARGET ATRP) were performed to graft polystyrene and poly(4-vinylpyridine) on the surface of cellulose nanocrystals (CNCs) to evaluate the potential benefits of each method. The polymer grafted CNCs and their corresponding free polymers initiated from sacrificial initiators were characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, dynamic light scattering, differential scanning calorimetry, thermogravimetric analysis, and elemental analysis, respectively...
February 1, 2019: Carbohydrate Polymers
https://www.readbyqxmd.com/read/30445768/densely-pegylated-polybenzofulvene-brushes-for-potential-applications-in-drug-encapsulation
#5
Marco Paolino, Giorgio Grisci, Federica Castriconi, Annalisa Reale, Germano Giuliani, Alessandro Donati, Claudia Bonechi, Gianluca Giorgi, Raniero Mendichi, Daniele Piovani, Antonella Caterina Boccia, Maurizio Canetti, Filippo Samperi, Sandro Dattilo, Cinzia Scialabba, Mariano Licciardi, Eugenio Paccagnini, Mariangela Gentile, Andrea Cappelli
The technique of grafting side chains onto a linear polymeric backbone is commonly used to confer to the new polymeric material with desired properties, such as tunable solubility, ionic charge, biocompatibility, or specific interactions with biological systems. In this paper, two new polybenzofulvene backbones were assembled by spontaneous polymerization of the appropriate benzofulvene monomers (4,6-PO- BF3k and 4',6-PO- BF3k ) bearing two clickable propargyloxy groups in different positions of the 3-phenylindene scaffold...
November 15, 2018: Pharmaceutics
https://www.readbyqxmd.com/read/30444350/ultrasensitive-photoelectrochemical-assay-with-ptb7-th-cdte-quantum-dots-sensitized-structure-as-signal-tag-and-benzo-4-chlorohexadienone-precipitate-as-efficient-quencher
#6
Mengjie Li, Xin Tian, Wenbin Liang, Ruo Yuan, Yaqin Chai
Herein, an ultrasensitive photoelectrochemical (PEC) assay was developed for the monitoring of microRNA-141 (miRNA-141) based on poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2- b:4,5- b']dithiophene-2,6-diyl- alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4- b]thiophene-4,6-diyl}/CdTe quantum dots ( PTB7-Th/CdTe QDs) sensitized structure as signal tag and the benzo-4-chlorohexadienone (4-CD) precipitate as efficient quencher. PTB7-Th and CdTe QDs were successively modified on the electrode surface to form a novel sensitized structure with eminent photovoltaic performances and surpassing film-forming ability...
November 29, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/30444347/flow-assisted-switchable-catalysis-of-metal-ions-in-a-microenvelope-system-embedded-with-core-shell-polymers
#7
Niraj K Vishwakarma, Yoon-Ho Hwang, Praveen Reddy Adiyala, Dong-Pyo Kim
Many efforts have been made on stimuli-responsive switchable catalysis to trigger catalytic activity over various chemical reactions. However, the reported light-, pH- or chemically responsive organocatalysts are mostly incomplete in the aspects of shielding efficiency and long-term performance. Here, we advance the flow-assisted switchable catalysis of metal ions in a microenvelope system that allows  the on-off catalysis mode on demand for long-lasting catalytic activity. Various metal-ion catalysts can be selectively embedded in a novel polymeric core-shell of the heteroarm star copolymer of poly(styrene) and poly(4-vinylpyridine) emanated from a polyhedral oligomeric silsesquioxane center...
November 29, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30441299/inkjet-printed-parallel-plate-capacitors-using-pvp-polymer-dielectric-ink-on-flexible-polyimide-substrates
#8
Ankita Mohapatra, K Sayema Tuli, Kwei-Yu Liu, Tomoko Fujiwara, W Robert Hewitt, Frank Andrasik, I Bashir Morshed
Inkjet printing (IJP) is an exciting new additive manufacturing technology that promises monolithic electronic circuit fabrication of $\mu \mathrm{m}$ thin low-cost large-area electronic low-cost body-worn flexible sensors. In this work, we demonstrate inkjet printed multilayer metal-dielectric-metal capacitors on flexible polyimide (PI) substrate by formulating a custom dielectric ink based on Poly 4-vinylphenol (PVP). Silver nanoparticle ink was used for printing theconductive parallel metal plates. We also demonstrate control over the capacitance values by varying the design parameters and succeeded in printing capacitors in the range 8...
July 2018: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/30433759/high-selectivities-among-monovalent-cations-in-dialysis-through-cation-exchange-membranes-coated-with-polyelectrolyte-multilayers
#9
Liu Yang, Chao Tang, Muhammad Ahmad, Andriy E Yaroshchuk, Merlin L Bruening
Cation-exchange membranes allow preferential passage of cations over anions, but they show minimal selectivity among cations, which limits their use in ion separations. Recent studies show that modification of cation-exchange membranes with polyelectrolyte multilayers leads to exceptional monovalent/divalent cation electrodialysis selectivities, but no studies report high selectivity among monovalent ions. This work demonstrates that adsorption of protonated poly(allylamine) (PAH)/poly(4-styrenesulfonate) (PSS) multilayers on Nafion membranes leads to high K+/Li+ selectivities in Donnan dialysis, where K+ and Li+ ions in a source phase pass through the membrane and exchange with Na+ ions in a receiving phase...
November 15, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30424417/a-0-35-%C3%AE-m-cmos-mems-oscillator-for-high-resolution-distributed-mass-detection
#10
Rafel Perelló-Roig, Jaume Verd, Joan Barceló, Sebastià Bota, Jaume Segura
This paper presents the design, fabrication, and electrical characterization of an electrostatically actuated and capacitive sensed 2-MHz plate resonator structure that exhibits a predicted mass sensitivity of ~250 pg·cm-2 ·Hz-1 . The resonator is embedded in a fully on-chip Pierce oscillator scheme, thus obtaining a quasi-digital output sensor with a short-term frequency stability of 1.2 Hz (0.63 ppm) in air conditions, corresponding to an equivalent mass noise floor as low as 300 pg·cm-2 . The monolithic CMOS-MEMS sensor device is fabricated using a commercial 0...
September 22, 2018: Micromachines
https://www.readbyqxmd.com/read/30417465/quaternization-of-a-polystyrene-block-poly-4-vinylpyridine-isoporous-membrane-an-approach-to-tune-the-pore-size-and-the-charge-density
#11
Zhenzhen Zhang, Md Mushfequr Rahman, Clarissa Abetz, Barbara Bajer, Jiali Wang, Volker Abetz
Isoporous integral asymmetric membranes derived from the self-assembly of block copolymers combined with the non-solvent-induced phase separation (SNIPS) have gained great attention. To extend their utility, good control over pore size and surface functionality in a facile manner is highly desirable. Here, an approach is proposed to achieve this by quaternization of the poly(4-vinylpyridine) moiety of a polystyrene-block-poly(4-vinylpyridine) SNIPS membrane using alkyl iodides via a scalable gas-solid heterogeneous reaction...
November 12, 2018: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/30384707/molecular-weight-dependence-of-chain-conformation-of-strong-polyelectrolytes
#12
Guofeng Xu, Jingfa Yang, Jiang Zhao
Using sodium polystyrene sulfonate (NaPSS) and quarternized poly 4-vinylpyridine (QP4VP) as model systems, the chain conformation of polyelectrolytes under finite salt concentrations is investigated at a single molecular level. By fluorescence correlation spectroscopy (FCS), the hydrodynamic radius ( R h ) of the samples with the molecular weight ranging more than one order of magnitude was measured. The variations of R h as a function of molecular weight reveal the molecular weight dependence: under moderate salt concentrations (such as 10-4 and 0...
October 28, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/30384693/comparison-of-kbr-and-nacl-effects-on-the-glass-transition-temperature-of-hydrated-layer-by-layer-assemblies
#13
Joshua T O'Neal, Kathryn G Wilcox, Yanpu Zhang, Ian M George, Jodie L Lutkenhaus
The influence of assembly and post-assembly conditions on the glass transition temperature of free-standing poly(diallyldimethyl ammonium) (PDADMA)/poly(4-styrene sulfonate) (PSS) layer-by-layer (LbL) films assembled in 0.5M NaCl and 0.5M KBr are explored using modulated differential scanning calorimetry. Upon completion, PDADMA/PSS LbL assemblies are hydrated using solutions containing various concentrations of KBr. The data indicate that water provides the primary driving force for changes in the glass transition temperature of completed films rather than the post-assembly salt type...
October 28, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/30380839/bioinspired-block-copolymer-for-mineralized-nanoporous-membrane
#14
Hui-Jun Zhou, Guan-Wen Yang, Yao-Yao Zhang, Zhi-Kang Xu, Guang-Peng Wu
Homoporous membranes fabricated by self-assembled block copolymers (BCPs) have gained growing attention for their easy availability of well-ordered nanostructures for precise separation. However, it remains a challenges to improve the mechanical integrity, hydrophilic properties, and pore functionalities of the existing systems. To this end, we report an organic-mineral composite hybrid nanoporous BCP membrane with attractive superhydrophilicity, mechanical stability, and fouling-resistance derived from a bioinspired block copolymer, poly(propylene carbonate)- block-poly(4-vinylcatechol acetonide) (PPC- b-PVCA)...
November 27, 2018: ACS Nano
https://www.readbyqxmd.com/read/30375604/bio-inspired-protonic-memristor-devices-based-on-metal-complexes-with-proton-coupled-electron-transfer
#15
Yusuke Hiruma, Kai Yoshikawa, Masa-Aki Haga
A new type of memristor inspired by bio-membranes is presented, based on the proton movement resulting from proton-coupled electron transfer (PCET) processes in dinuclear Ru complexes, whereby a two-terminal device based on said Ru complexes and a proton-conducting polymer was constructed as a proof-of-concept. Two ITO electrodes were modified separately with dinuclear Ru complexes that bear tetraphosphonic acid linkers at both ends and a 2,6,2',6'-tetrakis(benzimidazol-2-yl)-4,4'-bipyridine (RuNH-OH) or 1,3,1',3'-tetrakis(benzimidazol-2-yl)-5,5'-biphenyl (RuCH-OH) bridging ligand, and both ITO electrodes exhibit PCET processes with different Ru(ii/iii) redox potentials and pKa values...
October 30, 2018: Faraday Discussions
https://www.readbyqxmd.com/read/30366531/poly-4-vinylaniline-polyaniline-bilayer-functionalized-bacterial-cellulose-membranes-as-bioelectronics-interfaces
#16
Ana Rebelo, Yang Liu, Changqing Liu, Karl-Herbert Schäfer, Monika Saumer, Guang Yang
Bacterial cellulose (BC) fibers are chemically functionalized with poly(4-vinylaniline) (PVAN) interlayer for further enhancement of electrical conductivity and cell viability of polyaniline (PANI) coated BC nanocomposites. PVAN is found to have promoted the formation of a uniform PANI layer with nanofiber- and nanorod-like supramolecular structures, as an overall augmentation of PANI yield. Compositional and microstructural analysis indicates a PVAN/PANI bilayer of approximately 2 μm formed on BC. The solid-state electrical conductivity of such synthesized BC nanocomposites can be as high as (4...
January 15, 2019: Carbohydrate Polymers
https://www.readbyqxmd.com/read/30362254/identifying-an-optimal-seeding-protocol-and-endothelial-cell-substrate-for-biohybrid-lung-development
#17
Ulrich Zwirner, Klaus Höffler, Michael Pflaum, Sotirios Korossis, Axel Haverich, Bettina Wiegmann
INTRODUCTION: Several key prerequisites need to be fulfilled for the development of a biohybrid lung which can offer an actual alternative to lung transplantation. A major aspect is an optimized hemocompatibility of the device's artificial surfaces via endothelial cell seeding. In this study, four different types of polymeric gas exchange hollow fiber membranes (HFMs) were analyzed utilizing four different seeding protocols in order to identify the ideal combination for sufficient long-term endothelialization...
October 25, 2018: Journal of Tissue Engineering and Regenerative Medicine
https://www.readbyqxmd.com/read/30360076/long-term-stable-transferred-organic-photoactive-layer-based-photodiode-with-controlled-wetting-through-interface-stabilization
#18
Woongsik Jang, Dong Hwan Wang
The stamping-transfer process, which provides a precise patterning of the target material without the limitation of an underlying layer, has attracted significant attention for large-scale roll-to-roll fabrication. Despite the need to minimize the peeling energy, expressed as the sum of adhesion energies, for a simple transfer process, many studies have not considered this effect. In this study, we introduced wetting coefficient related with adhesions between polymers for transfer design of organic photo-sensitive materials...
October 16, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30338970/template-confined-growth-of-poly-4-aminodiphenylamine-nanosheets-as-positive-electrode-toward-superlong-life-asymmetric-supercapacitor
#19
Hui Peng, Rui Zhao, Jing Liang, Sihan Wang, Fei Wang, Jiezi Zhou, Guofu Ma, Ziqiang Lei
Two-dimensional conducting polymers nanosheet prepared by the soft-template-assisted technique in aqueous system still has rarely been reported, especially the formation of nanosheets structure by protonic acid assisted controlling the stability of the micelles method. Herein, a facile, one-step, bottom-up approach is developed to synthesize novel and uniform conductive poly(4-aminodiphenylamine) (P(4-ADPA)) nanosheets with controlled morphology via regulating the proton acid concentration during the self-assembly of surfactant lamellar micelles...
October 31, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/30338320/renewable-boronic-acid-affiliated-glycerol-nano-adsorbents-for-recycling-enzymatic-catalyst-in-biodiesel-fuel-production
#20
Lei Liu, Gaojian Ma, Min Zeng, Wei Du, Jinying Yuan
Nano-adsorbents composed of poly(4-vinylphenyl boronic acid) shell and silica core efficiently remove residual glycerol from a lipase catalyst layer in biodiesel fuel production, resulting in excellent lipase recycling. The subsequent CO2-acidolysis endows the adsorbents with sustainable renewability.
November 1, 2018: Chemical Communications: Chem Comm
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