Evaluation of surface modification by electrokinetic measurements

Bellmann, Cornelia; Klinger, Christian; Opfermann, Andreas; Böhme, Frank; Adler, Hans-Jürgen P.

doi:10.1016/s0300-9440(01)00248-x

Cited by 48 publications

(25 citation statements)

References 13 publications

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“…3. As expected, 9 AlA-functionalized beads show a shift to positive potentials (with respect to untreated PS macrospheres), while AcA films are shifted towards negative values. At physiological pH, both AlA and AcA beads functionalized at 100 W showed shifts of š10 mV, respectively.…”

Section: Zeta Potentialsupporting

confidence: 80%

Plasma functionalization, surface characterization and protein retention of multiple‐sized polymer beads

Manso

Rodríguez²,

Paul³

et al. 2006

Surface & Interface Analysis

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The surfaces of several types of polymer beads used in solid-phase extraction processes were modified with functional groups. Porous polystyrene (PS) macrospheres and polyvinylchloride (PVC) microspheres were plasma-modified in a fluidized-bed reactor by functionalization with allylamine (AlA) or acrylic acid (AcA). The surface compositions, as measured by XPS, showed the successful incorporation of the functional groups, and the numbers of these groups were assayed by derivatization onto model planar substrates. Furthermore, the influence on the surface Zeta potential of the beads was measured, which showed shifts of ±10 mV at physiological pH by the immobilized amino or carboxylic groups, respectively. A bovine serum albumin-fluorescein conjugate was used in a liquid chromatography system to evaluate the protein retention capacity. The results indicate higher protein retention on plasma-treated beads with respect to the untreated materials, and on PS when compared to PVC. Particularly high retention is obtained with AlA functionalization at 100 W.

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Section: Zeta Potentialsupporting

confidence: 80%

Plasma functionalization, surface characterization and protein retention of multiple‐sized polymer beads

Manso

Rodríguez²,

Paul³

et al. 2006

Surface & Interface Analysis

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“…Details of the measuring technique and the used device are reported in [9][10][11]. Two small pieces of coated or uncoated wafer (10 × 20 mm) were arranged parallel face to face to build a streaming channel inside the cell.…”

Section: Electrokinetic Studiesmentioning

confidence: 99%

Electrokinetic investigation of surfactant adsorption

Bellmann

Synytska

Caspari

et al. 2007

Journal of Colloid and Interface Science

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“…During the measurement, the electrolyte solution is forced through the packed fibre bed which partially shears off the diffusive part of the electrochemical double layer, which gives rise to the streaming potential (U s ). The theoretical background (Hunter 1981) and further experimental details are reported elsewhere (Jacobasch et al 1996;Bellmann et al 2002). Lignocellulosic fibres swell in water, causing a decay of the f = f(t) that can be described according to Kanamaru (1960) by the following equation:…”

Section: F-potential Measurementsmentioning

confidence: 99%

Wetting behaviour, moisture up-take and electrokinetic properties of lignocellulosic fibres

Baltazar‐y‐Jimenez

Bismarck

2006

Cellulose

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The wetting and moisture up-take behaviour, as well as the electrokinetic properties of various lignocellulosic fibres were characterised. Knowledge of surface and water uptake properties of this kind of materials will help to tailor their potential use in different end user applications. The surface tension of the fibres was determined from wetting measurements using the capillary rise technique. The wetting data were used to determine the surface tension of the fibres. Our results show that the surface tension of the lignocellulosic fibres is a linear function of their cellulose content. Zeta-potential measurements were exploited to characterise the surface chemistry of the fibres. Measuring the zeta-potential as function of time enables the rapid assessment of the water up-take, i.e. the swelling behaviour of the fibres. The results obtained by the zeta potential measurements correlate, with the exception of flax, in a linear manner with the results obtained from conventional moisture uptake measurements. Even though all lignocellulosic fibres are very hydrophilic due to the presence of polar oxygen containing groups they have different grades of hydrophilicity, which is also reflected in the different water uptake capabilities measured.The wetting, moisture uptake and electrokinetic properties of the lignocellulosic fibres are determined by the availability of the surface functional groups present, which is usually consequence of the processes used to separate, and extract the fibres from the plant (retting), as well as any further processing used to improve the fibre quality.

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Evaluation of surface modification by electrokinetic measurements

Cited by 48 publications

References 13 publications

Plasma functionalization, surface characterization and protein retention of multiple‐sized polymer beads

Plasma functionalization, surface characterization and protein retention of multiple‐sized polymer beads

Electrokinetic investigation of surfactant adsorption

Wetting behaviour, moisture up-take and electrokinetic properties of lignocellulosic fibres

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