Health & Environmental Research Online (HERO)


Per- and Polyfluoroalkyl Substances (PFAS)


145 References Were Found:

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Liver and kidney cells cultures in a new perfluoropolyether biochip

Authors: Jellali, R; Paullier, P; Fleury, MJ; Leclerc, E (2016) HERO ID: 3860633

[Less] Although microfluidics represents a promising technology for drug screening industry and toxicity tests, . . . [More] Although microfluidics represents a promising technology for drug screening industry and toxicity tests, their industrial applications using cells are limited by drawbacks of the weakly mass production capability of the biochips. In this work, we report the fabrication of resistant fluorinated microfluidic devices using a material widely used in polymer industries. To build the microdevices, two patterned layers with precise and regular microchannels were developed by photocuring of perfluoropolyethers (PFPEs). These layers were successfully sealed by UV irradiation. Then, Liver HepG2/C3A and kidney MDCK cells were cultured in PFPE biochips. The growth, cell viability and basal metabolism of cells cultured in PFPE biochips were studied and compared with results obtained using polydimethylsiloxane (PDMS) biochips. The results have shown that the cells can attach to the biochip bottom, spread, and proliferate well in PFPE biochip (similar to the cells in PDMS biochip). Furthermore, metabolisms of cell cultures in PFPE biochip, such as glucose consumption, albumin and urea productions, were proved similar to the results obtained in PDMS biochips. These results highlighted the functionality of the HepG2/C3A and MDCK cells in PFPE microfluidic devices and illustrated their potential to replace PDMS devices. (C) 2016 Elsevier B.V. All rights reserved.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Rheological Properties of PFPE Lubricants at Elevated Temperatures

Authors: Chung, PilS; Song, W; Biegler, LT; Jhon, MS (2016) HERO ID: 3860652

[Less] During the intermittent contact between the head and the disk of the hard disk drive (HDD), the perfluoropolyether . . . [More] During the intermittent contact between the head and the disk of the hard disk drive (HDD), the perfluoropolyether (PFPE) lubricant experiences shear/ elongation deformation. Therefore, the molecular rheology of PFPE becomes critically important in designing optimal lubricants that control the friction and wear. In this paper, we examine, for the first time, the rheological responses of nanoblended PFPEs, including storage and loss moduli (G' and G ''), by monitoring the time-dependent stress-strain relationship via nonequilibrium molecular dynamics simulations. We observed that the nonfunctional PFPEs (Fomblin Z-type) exhibit liquid-like behavior, while agglomeration behavior was observed for the functional PFPEs (Fomblin Zdol-type). In addition, strong endgroup couplings due to functional endgroup weaken as the temperature increases. For binary blended PFPEs, we also observed similar phenomena, which strongly depends on the blend ratio and imposed condition (e.g., temperature and oscillatory frequency). We established a finger print analysis via G'-G '' plots for different blend ratios and temperatures. By analyzing the blended PFPE relaxation processes, our results provide the optimal parameters for lubricant selection criteria to enhance the HDD performance.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Heparin micropatterning onto fouling-release perfluoropolyether-based polymers via photobiotin activation

Authors: Credi, C; De Marco, C; Molena, E; Pla Roca, M; Samitier Martí, J; Marques, J; Fernàndez-Busquets, X; Levi, M; Turri, S (2016) Colloids and Surfaces B: Biointerfaces 146:250-259. HERO ID: 3860593

[Less] A simple method for constructing versatile ordered biotin/avidin arrays on UV-curable perfluoropolyethers . . . [More] A simple method for constructing versatile ordered biotin/avidin arrays on UV-curable perfluoropolyethers (PFPEs) is presented. The goal is the realization of a versatile platform where any biotinylated biological ligands can be further linked to the underlying biotin/avidin array. To this end, microcontact arrayer and microcontact printing technologies were developed for photobiotin direct printing on PFPEs. As attested by fluorescence images, we demonstrate that this photoactive form of biotin is capable of grafting onto PFPEs surfaces during irradiation. Bioaffinity conjugation of the biotin/avidin system was subsequently exploited for further self-assembly avidin family proteins onto photobiotin arrays. The excellent fouling release PFPEs surface properties enable performing avidin assembly step simply by arrays incubation without PFPEs surface passivation or chemical modification to avoid unspecific biomolecule adsorption. Finally, as a proof of principle biotinylated heparin was successfully grafted onto photobiotin/avidin arrays.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Direct photo-patterning of hyaluronic acid baits onto a fouling-release perfluoropolyether surface for selective cancer cell capture and immobilization

Authors: Credi, C; De Marco, C; Molena, E; Nava, MM; Raimondi, MT; Levi, M; Turri, S (2016) Materials Science and Engineering C: Materials for Biological Applications 62:414-422. HERO ID: 3860594

[Less] A simple photolithographic process for directly patterning glycidyl methacrylate modified hyaluronic . . . [More] A simple photolithographic process for directly patterning glycidyl methacrylate modified hyaluronic acid features onto UV curable perfluoropolyether-based surfaces is presented. Due to the versatility of the developed method, HA spotted areas with different geometrical features could be rapidly and inexpensively designed. In addition, the excellent antifouling and fouling-release properties of the substrates enabled direct HA baits photo-grafting onto PFPEs without further surface passivation or chemical modification to avoid not specific adsorption. The aim of the study was to locally switch the surface properties of the PFPEs from cells and protein repulsive to adherent. Particularly, we exploited HA well-known preferential interactions with CD44 transmembrane receptors to selectively immobilize cancer cells. Living cell arrays offer a higher-resolution visualization of HA-CD44 interactions and may provide a deep insight into understanding molecular mechanisms needed to develop selective therapies and diagnosis against tumor growth.

Journal Article
Journal Article

High Resolution Mass Spectrometry of Polyfluorinated Polyether-Based Formulation

Authors: Dimzon, IK; Trier, X; Frömel, T; Helmus, R; Knepper, TP; de Voogt, P (2016) 27:309-318. HERO ID: 3860595

[Less] High resolution mass spectrometry (HRMS) was successfully applied to elucidate the structure of a polyfluorinated . . . [More] High resolution mass spectrometry (HRMS) was successfully applied to elucidate the structure of a polyfluorinated polyether (PFPE)-based formulation. The mass spectrum generated from direct injection into the MS was examined by identifying the different repeating units manually and with the aid of an instrument data processor. Highly accurate mass spectral data enabled the calculation of higher-order mass defects. The different plots of MW and the nth-order mass defects (up to n = 3) could aid in assessing the structure of the different repeating units and estimating their absolute and relative number per molecule. The three major repeating units were -C2H4O-, -C2F4O-, and -CF2O-. Tandem MS was used to identify the end groups that appeared to be phosphates, as well as the possible distribution of the repeating units. Reversed-phase HPLC separated of the polymer molecules on the basis of number of nonpolar repeating units. The elucidated structure resembles the structure in the published manufacturer technical data. This analytical approach to the characterization of a PFPE-based formulation can serve as a guide in analyzing not just other PFPE-based formulations but also other fluorinated and non-fluorinated polymers. The information from MS is essential in studying the physico-chemical properties of PFPEs and can help in assessing the risks they pose to the environment and to human health. Graphical Abstract ᅟ.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Molecularly thin fluoro-polymeric nanolubricant films: tribology, rheology, morphology, and applications

Authors: Chung, PS; Jhon, MS; Choi, HJ (2016) Soft Matter 12:2816-2825. HERO ID: 3860596

[Less] Molecularly thin perfluoropolyether (PFPE) has been used extensively as a high-performance lubricant . . . [More] Molecularly thin perfluoropolyether (PFPE) has been used extensively as a high-performance lubricant in various applications and, more importantly, on carbon overcoats to enhance the reliability and lubrication of micro-/nanoelectro-mechanical systems, where the tribological performance caused by its molecular architecture is a critical issue, as are its physical properties and rheological characteristics. This Highlight addresses recent trends in the development of fluoro-polymeric lubricant films with regard to their tribology, rheology, and physio-chemical properties as they relate to heat-assisted magnetic recording. Nanorheology has been employed to examine the dynamic response of nonfunctional and functional PFPEs, while the viscoelastic properties of nanoscale PFPE films and the relaxation processes as a function of molecular structure and end-group functionality were analyzed experimentally; furthermore, the characteristics of binary blends were reported.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Study on Nanometer-Thick Room-Temperature Ionic Liquids (RTILs) for Application as the Media Lubricant in Heat-Assisted Magnetic Recording (HAMR)

Authors: Gong, X; West, B; Taylor, A; Li, Lei (2016) HERO ID: 3860628

[Less] Nanometer-thick room-temperature ionic liquids (RTILs) have been studied for potential application as . . . [More] Nanometer-thick room-temperature ionic liquids (RTILs) have been studied for potential application as media lubricants for heat-assisted magnetic recording (HAMR) in the hard disk drive (HDD) industry. The RTILs containing fluorinated anions are readily solvable in Vertrel XF solvent and can be applied on the media by dip-coating, which is compatible to the current industry process. The thermal stability, topography and tribological performance of the RTILs nanofilms have been characterized by thermogravametric analysis (TGA), ellipsometry, atomic force microscopy (AFM) and nanotribometry. The experimental results showed that RTILs are thermally more stable than the state-of-the-art media lubricants in HDDs, i.e., perfluoropolyethers (PFPEs) such as diolic perfluoropoly(oxyethylene-ran-oxymethylene) commercially known as Zdol. The lubricant uniformity of most studied RTILs is better than that of Zdol, and no dewetting is observed even when the RTIL nanofilm is as thick as 10 nm. The friction coefficient of subnanometer-thick RTILs is lower than that of Zdol. The structure-property relationship and the possible structure design for the future improvement have been discussed.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Atomistic and Molecular Effects on the Surface Morphology and Film Conformation of Perfluoropolyether Lubricant Layer

Authors: Chung, PilS; Park, S; Vemuri, SH; Jhon, MS (2015) HERO ID: 3860651

[Less] In this paper, we analyzed atomistic and molecular architectural effects on the film microstructure . . . [More] In this paper, we analyzed atomistic and molecular architectural effects on the film microstructure and morphological properties for the monolayer perfluoropolyether (PFPE) lubricant film by investigating PFPEs with different molecular structures and functionalities (Zdol, Ztetraol, Ztetraol multidentate, and TA-30) via large-scale coarse-grained bead-spring molecular dynamics originating from the atomistic theory. Film surface morphology was examined by average height and root mean square roughness, and the internal clusters of functional groups on the surface were characterized by the radial distribution function of functional groups, followed by the quantitative estimation of adhesion ratio and coordination number. We also illustrate the effects of molecular structure on the film conformation, which is useful to molecular design criteria for the head-disk interface.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Effect of end-groups on simultaneous oleophobicity/hydrophilicity and anti-fogging performance of nanometer-thick perfluoropolyethers (PFPEs)

Authors: Wang, Y; Knapp, J; Legere, A; Raney, J; Li, Lei (2015) HERO ID: 3860670

[Less] Simultaneously oleophobic/hydrophilic coatings are highly desirable in many important applications, . . . [More] Simultaneously oleophobic/hydrophilic coatings are highly desirable in many important applications, e.g., anti-fogging. However, to date, such coatings have been rarely reported and the underlying mechanisms remain unclear. In the current paper, the wetting behavior of three nanometer-thick perfluoropolyether (PFPE) polymers with the same backbone but different end-groups has been studied by contact angle tests and the underlying mechanisms governing the simultaneous oleophobicity/hydrophilicity have been investigated. The experimental results indicated that the end-groups of the nanometer-thick PFPEs are critical to the simultaneous oleophobicity/hydrophilicity. PFPE polymers with different end-groups can interact with the substrate in very different ways, resulting in different packing orders and thus different inter-chain distances within the polymer nanofilms. If the inter-chain distance is appropriately small, smaller water molecules penetrate the nanofilms quickly while larger oil molecules penetrate the nanofilms much more slowly. As a result, the surface shows a higher oil contact angle (OCA) than WCA, i.e., simultaneous oleophobicity/hydrophilicity. Moreover, the effect of simultaneous oleophobicity/ hydrophilicity on the long-term anti-fogging capability has been studied by X-ray photoelectron spectroscopy (XPS) and anti-fogging tests. The results indicated that the unique simultaneous oleophobicity/hydrophilicity reduces the airborne hydrocarbon contamination and therefore improves the long-term anti-fogging performance.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Film Conformation and Dynamic Properties of Atomistically Architectured Perfluoropolyethers on the Carbon Overcoated Surfaces

Authors: Chung, PilS; Jhon, MS (2015) HERO ID: 3860683

[Less] To improve chemical and thermal stability under harsh conditions, conventional linear perfluoropolyether . . . [More] To improve chemical and thermal stability under harsh conditions, conventional linear perfluoropolyether (PFPE) lubricants with chain-like structures need to be molecularly modified. We investigated the molecular conformations and dynamic properties of star-like PFPEs (i.e., TA-30 and QA-40) chosen as a candidate lubricant material for the heat-assisted magnetic recording system and compared those results to the other molecularly architectured PFPEs (i.e., Zdol, Ztetraol, and ZTMD) via multiscale modeling methodology. Due to the improved adhesion of the extra arms to the surface, star-like PFPEs exhibit excellent thermal stability, while additional functional groups cause agglomeration by drastically decreasing mobility on the carbon overcoat. The effect of PFPE molecular structures on the static and dynamic responses examined here could provide the molecular design criteria for the advanced head-disk interface design.