Evaluation of surface characteristics of polymers in water. Measurement of surface free energy in water

Nakamae, Katsuhiko; Miyata, Takashi; Ootsuki, Norihito

doi:10.1002/marc.1993.030140708

Cited by 23 publications

(6 citation statements)

References 14 publications

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“…Contact Angle Measurement in Water. The static contact angles of methylene iodide and air bubbles on PFA-C y films in water were measured by Hamilton's method , using DSA10. The sample was immersed in water ( T = 300 K) for 120 min, and the contact angle was measured.…”

Section: Methodsmentioning

confidence: 99%

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Molecular Aggregation Structure and Surface Properties of Poly(fluoroalkyl acrylate) Thin Films

et al. 2005

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The effects of side chain length on the molecular aggregation states and surface properties of poly(fluoroalkyl acrylate) [PFA-Cy, where y is the fluoromethylene number of the Rf groups] thin films were systematically investigated. Spin-coated PFA-Cy thin films were characterized by static and dynamic contact angle measurements, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry, and wide-angle X-ray diffraction. The receding contact angles showed small values for PFA-Cy with short side chain (y e 6) and increased for ones with y g 8. It has been revealed that PFA-Cy with y g 8 was crystallized and formed ordered structures. These results suggest that the water-repellent mechanism of PFA-Cy can be attributed to the presence of highly ordered fluoroalkyl chains at the outermost surfaces. The results of XPS in the dried and hydrated states and the contact angle measurement in water indicate that the contact angle for water is lowered by exposure of the carbonyl groups to the water interface through reorientation of short fluoroalkyl chains.

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Section: Methodsmentioning

confidence: 99%

“…The surface free energy in water was calculated from the static contact angles using the geometrical mean approach. 19…”

Section: T H Imentioning

confidence: 99%

Molecular Aggregation Structure and Surface Properties of Poly(fluoroalkyl acrylate) Thin Films

et al. 2005

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“…The contact angles were determined from the advancing contact angle (θ a ) and receding contact angle (θ b ) by eq 1 In this study, the surface free energy was obtained from the contact angles of water and formamide with eq 2, which was proposed by Owens et al, − as follows: where γ s and γ l are the surface free energy of the solid and the liquid, and γ s d , γ s p , γ l d , and γ l p are the dispersion force components and polar force components of the surface free energy of the solid and the liquid, respectively. The dispersion force component and polar force component of the surface free energy of water are 21.8 and 51.0 erg/cm 2 , respectively, and those of formamide are 39.5 and 18.7 erg/cm 2 , respectively. , …”

Section: Methodsmentioning

confidence: 99%

“…In this study, the surface free energy was obtained from the contact angles of water and formamide with eq 2, which was proposed by Owens et al, [33][34][35][36][37] as follows:…”

Section: Methodsmentioning

confidence: 99%

“…Generally, surface properties of multicomponent polymers are quite different from their bulk properties because of the surface localization of a component. − For example, a fluorine-containing component in a multicomponent polymer is preferentially concentrated at its surface to minimize the surface free energy. Therefore, the fluorine-containing polymer that is spontaneously localized at the polymer surface might enable a simple surface modification of pervaporation membranes.…”

Section: Introductionmentioning

confidence: 99%

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Surface Modification of Microphase-Separated Membranes by Fluorine-Containing Polymer Additive and Removal of Dilute Benzene in Water through These Membranes

2001

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Hydrophobically surface-modified membranes were prepared by adding a fluorine-containing graft copolymer into a microphase-separated membrane consisting of poly(dimethylsiloxane) (PDMS) and poly(methyl methacrylate) (PMMA). This study focuses on the effects of surface characteristics and microphase separation of the surface-modified membranes on their permselectivity for a dilute aqueous solution of benzene in pervaporation. Contact angle measurements and X-ray photoelectron spectroscopy revealed that the addition of a fluorine-containing copolymer produced a hydrophobic surface at the membrane air side due to its surface localization. It became apparent from transmission electron microscopy that adding a fluorine-containing copolymer of less than 1.2 wt % did not affect the morphology of the microphase-separated membrane, but adding the copolymer over 1.2 wt % resulted in a morphological change from a continuous PDMS phase to a discontinuous PDMS phase. The addition of a small amount of fluorine-containing copolymer into the microphase-separated membranes enhanced both the permeability and selectivity for a dilute aqueous solution of benzene in pervaporation because of their hydrophobic surfaces and microphase-separated structures. Specifically, the microphase-separated membrane containing 1.2 wt % of fluorine-containing copolymer concentrated from an aqueous solution of 0.05 wt % benzene to 70 wt % benzene and removed benzene in water very effectively. This paper also discusses the effect of the asymmetric surface structure of the hydrophobically surface-modified membranes on their permselectivity.

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Surface properties of perfluoroalkylethyl acrylate/n-alkyl acrylate copolymers

Morita

Ogisu

Kubo

1999

J. Appl. Polym. Sci.

129

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Wetting behavior of perfluoroalkylethyl acrylate (FA)/n-alkyl acrylate (AA) copolymers with the various length of side chains of the AAs is discussed from a standpoint of surface molecular mobility. The copolymerization reactivity ratio indicates that these polymers are random copolymers. The surface properties were studied by measuring dynamic contact angle, static contact angle and freeze-dried X-ray photoelectron spectroscopy, and the bulk properties by wide-angle X-ray diffraction and differential scanning calorimetry. The advancing contact angles for water were independent of side-chain length of AAs and were almost constant at 120°. We have attributed this phenomenon to the orientation of perfluoroalkyl groups (R f groups, C x F 2xϩ1 ) in air, which is independent of side-chain length of AAs. On the contrary, the receding contact angles showed small values of about 45°when n numbers below 8 and increased when n numbers above 12. This can be explained as follows. High wettability during the receding process at the n numbers below 8 results from regression of R f groups at the water-solid interface caused by minimization of the interface free energy. The low wettability during the receding process at the n numbers above 12 shows that R f groups cannot regress due to its crystallization. This mechanism is also supported by other measurements.

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Evaluation of surface characteristics of polymers in water. Measurement of surface free energy in water

Cited by 23 publications

References 14 publications

Molecular Aggregation Structure and Surface Properties of Poly(fluoroalkyl acrylate) Thin Films

Molecular Aggregation Structure and Surface Properties of Poly(fluoroalkyl acrylate) Thin Films

Surface Modification of Microphase-Separated Membranes by Fluorine-Containing Polymer Additive and Removal of Dilute Benzene in Water through These Membranes

Surface properties of perfluoroalkylethyl acrylate/n-alkyl acrylate copolymers

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