Direct Measurement of Thermoelastic Properties of Glassy and Rubbery Polymer Brush Nanolayers Grown by “Grafting-from” Approach

LeMieux, Melburne C.; Minko, Sergiy; Usov, Denys; Stamm, Manfred; Tsukruk, Vladimir V.

doi:10.1021/la0340504

Cited by 67 publications

(76 citation statements)

References 58 publications

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“…Similarly, stiffness measurements have been exploited to characterize heterogeneity in thin film blends of polystyrene and polybutadiene [288,289] and in polymer brush layers from poly(styrene-co-pentafluorostyrene) and polymethylacrylate [290]. In this last study the temperature dependence of the elastic response of polymer brushes also is addressed, showing that changes in the elastic behavior of the polymer sample, probed through force-displacement curves, can be exploited to determine the glass transition temperature of the polymer.…”

Section: Resultsmentioning

confidence: 99%

Force measurements with the atomic force microscope: Technique, interpretation and applications

Butt

Cappella

Kappl

2005

Surface Science Reports

3,246

2,949

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Section: Resultsmentioning

confidence: 99%

Force measurements with the atomic force microscope: Technique, interpretation and applications

Butt

Cappella

Kappl

2005

Surface Science Reports

3,246

2,949

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“…[20] Similar elastic moduli were observed by AFM nanoindentation in the case of poly(styrene-co-2,3,4,5,6-pentafluorostyrene) and poly(methylacrylate). [22] As the brush height is often limited to several tens of nanometers, substrate effects may play a role in the determination of the elastic moduli by atomic force microscopy (AFM) nanoindentation. As a rule of thumb, penetrations should be limited to 10% of the film thickness to avoid this effect, although up to 35% can be reached for the combination of a soft film on a stiff substrate.…”

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confidence: 99%

Nanomechanical Properties of Oligo(ethylene glycol methacrylate) Polymer Brush‐Based Biointerfaces

et al. 2011

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Protein resistant polymer brushes of poly(diethylene glycol methylether methacrylate) (DEGMA) are synthesized by surface‐initiated polymerization (SIP) on gold and are thoroughly characterized with particular attention to the nanomechanical properties. Compared to the well known brushes of poly(oligoethylene glycol methylether methacrylate) (POEGMA) on gold, PDEGMA brushes grow faster and yield higher final brush heights. In confocal fluorescence microscopy experiments it is shown that both types of brushes possess similar low non‐specific adsorption levels of labeled bovine serum albumin (BSA) from buffer. While the surface stiffness evaluated by depth sensing indentation in the dry state suggests that side chain crystallization imparts high stiffness to the POEGMA brush, PDEGMA brushes behave similar to poly(methyl methacrylate) (PMMA) brushes of comparable thickness. In the wet state PDEGMA brushes are shown to possess an elastic modulus of 800 kPa, as estimated by AFM nanoindentation, which is smaller than that of POEGMA (3 000 kPa). Expanding these brushes to end‐functional polymers with recently developed block copolymer brush approaches, tailored soft biointerfaces can be generated for cell ‐ surface interaction and cell culture studies.

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“…19 A similar result has also been observed on the poly(2,2,2-trifluoroethyl methacrylate)-block-polyacrylamide brush surface on flat silicon wafer by Wang et al 20 Tsukruk et al prepared thick (50-90 nm) poly(styrene-co-PFS) brush to investigate the thermal and mechanical properties of the brush surface by AFM-based techniques using a thermal probe. 21 In this paper, we prepared the PFA-C 8 brush thin films with a thickness of 4-50 nm by surface-initiated ATRP to analyze the molecular aggregation states of PFA-C 8 brush thin films with R f groups by contact angle measurements, WAXD, X-ray reflectivity (XR), and in-plane and out-of plane GIXD. This research will demonstrate the relationship between the brush thickness and the molecular aggregation state of R f groups to show the gradient structure along with the distance from the outermost brush surface to the migrated substrate interface.…”

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Molecular Aggregation State of Surface-grafted Poly{2-(perfluorooctyl)ethyl acrylate} Thin Film Analyzed by Grazing Incidence X-ray Diffraction

Yamaguchi

Honda

Kobayashi

et al. 2008

Polym J

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Surface-initiated atom transfer radical polymerization of 2-(perfluorooctyl)ethyl acrylate on a flat silicon wafer was carried out to give poly{2-(perfluorooctyl)ethyl acrylate} (PFA-C 8 ) brush thin film with three different thicknesses of 4, 11, and 43 nm, respectively. The water contact angle of the PFA-C 8 brush surface was 120. The molecular aggregation state of the perfluoroalkyl (R f ) group of PFA-C 8 brush was analyzed by X-ray reflectivity (XR), wide-angle X-ray diffraction, and grazing incidence X-ray diffraction (GIXD) measurements. XR analysis revealed that R f groups at the air/brush interface formed a densely packed structure, while a relatively low-density region was generated at the brush/substrate interface. The peaks of in-plane GIXD for brush films with thicknesses of 11 and 43 nm were observed at q xy ¼ 12:5 nm À1 , which indicated that R f groups at the outermost surface oriented perpendicular to the surface of silicon substrate. In an out-of-plane diffraction profile of the 43 nm-thick PFA-C 8 brush film, peaks corresponding to a periodic length of the bilayer lamellae were observed. Therefore, R f groups of the thicker brush film were crystallized and formed ordered bilayer lamellar structure at the outermost surface. In contrast, no diffraction pattern was observed from the PFA-C 8 at a thickness of 4 nm by WAXD and GIXD. These results indicate that an amorphous layer was formed at the interface of the brush/substrate. The R f groups at the anchoring region of the brush could not form a sufficiently ordered structure due to immobilization of brush chain ends on the substrate. It was suggested that the R f groups in a PFA-C 8 brush thin film at the outermost surface aggregated in a different manner from those in the anchoring region.KEY WORDS: Perfluoroalkyl Acrylate / Polymer Brush / Water-Repellant Surface / X-Ray Reflectivity / Grazing Incidence X-ray Diffraction / Surface-initiated Polymerization / It has been well-known that polymers with perfluoroalkyl (R f ) groups show excellent chemical and thermal stability, nonadhesive properties, low friction coefficients, low surface free energy, and antifouling behavior. These properties of fluorinated polymers are primarily caused by unique C-F bonds which have a large binding energy and quite a low dielectric constant due to short bonding distance between carbon and fluorine atom with high electro negativity. However, the surface component, orientation packing, and end groups also affect the surface behavior of the polymer films.1-3 When the surface is uniformly covered with trifluoromethyl (CF 3 ) groups, 4 excellent water repellency and a very low energy surface can be achieved. 5 In the case of poly(fluoroalkyl acrylate)s with long R f groups, the molecular aggregation state of the R f groups at the side chains affects the surface wettablity. 6,7 We have recently reported the relationship between the molecular aggregation states and the water repellency of poly(perfluoroalkyl acrylate) (PFA-C y , where y is the number of fluoromethylene...

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Direct Measurement of Thermoelastic Properties of Glassy and Rubbery Polymer Brush Nanolayers Grown by “Grafting-from” Approach

Cited by 67 publications

References 58 publications

Force measurements with the atomic force microscope: Technique, interpretation and applications

Force measurements with the atomic force microscope: Technique, interpretation and applications

Nanomechanical Properties of Oligo(ethylene glycol methacrylate) Polymer Brush‐Based Biointerfaces

Molecular Aggregation State of Surface-grafted Poly{2-(perfluorooctyl)ethyl acrylate} Thin Film Analyzed by Grazing Incidence X-ray Diffraction

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