Electron beam-based functionalization of polymer membranes

Schulze, Agnes; Marquardt, Barbara; Went, Marco; Prager, Andrea; Buchmeiser, Michael R.

doi:10.2166/wst.2012.890

Cited by 33 publications

(26 citation statements)

References 5 publications

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“…This way, links between the polymer matrix and the enzyme can be formed that are assumed to be side-unspecific. Previous work demonstrated the formation of covalent chemical bonds between the membrane polymer and the immobilized molecules by XPS analysis, which was supported by extensive extraction experiments [22][23][24]26,47]. It is worth emphasizing that the use of an aqueous system is a crucial requirement since different results were obtained in the dry state as also reported in the literature [48].…”

Section: Resultssupporting

confidence: 59%

“…The EB treatment results in the generation of a mixture of ions, excited m described for the radiolysis of water [45] ensuring the activation of both the dis well as of the membranes [22][23][24][27][28][29]47]. The formed radicals/activated s reactions, such as cross-linking or recombination reactions.…”

Section: Resultsmentioning

confidence: 99%

“…This technology enables direct immobilization of functional organic molecules [22,23], engineering polymers [24], or even biomolecules [25,26] on a membrane's surface. The use of low-energy EB radiation combines surface activation (formation of activated species) of the membrane polymer and simultaneous covalent immobilization of the desired compounds from an aqueous system.…”

Section: Polymers 2015 7mentioning

confidence: 99%

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Biocatalytic Self-Cleaning Polymer Membranes

et al. 2015

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Polymer membrane surfaces have been equipped with the digestive enzyme trypsin. Enzyme immobilization was performed by electron beam irradiation in aqueous media within a one-step method. Using this method, trypsin was covalently and side-unspecific attached to the membrane surface. Thus, the use of preceding polymer functionalization and the use of toxic solvents or reagents can be avoided. The resulting membranes showed significantly improved antifouling properties as demonstrated by repeated filtration of protein solutions. Furthermore, the biocatalytic membrane can be simply "switched on" to actively degrade a fouling layer on the membrane surface and regain the initial permeability. The membrane pore structure (pore size and porosity) was neither damaged by the electron beam treatment nor blocked by the enzyme loading, ensuring a stable membrane performance.

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Section: Resultssupporting

confidence: 59%

Section: Resultsmentioning

confidence: 99%

Section: Polymers 2015 7mentioning

confidence: 99%

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Biocatalytic Self-Cleaning Polymer Membranes

et al. 2015

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“…However, this hydrophobicity leads to hydrophobic interactions with, e.g., proteins resulting in a fouling layer precipitated on the membrane surface accompanied by a decreased membrane performance [1,2]. The common way to face this problem is to hydrophilize the hydrophobic membrane material [3][4][5][6][7][8][9][10] with different modification methods like grafting reactions [6,[8][9][10][11][12], electron beam (EB) irradiation [13,14] or plasma treatment [5,[15][16][17][18][19][20]. The hydrophilized membrane surfaces then show an increased fouling resistance due to the buildup of a water film on the membrane surface, which repels hydrophobic fouling reagents [21].…”

Section: Membrane Surface Hydrophilicity and Surface Chargementioning

confidence: 99%

Tailoring Membrane Surface Charges: A Novel Study on Electrostatic Interactions during Membrane Fouling

et al. 2015

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Abstract:In this work we aim to show that the overall surface potential is a key factor to understand and predict anti-fouling characteristics of a polymer membrane. Therefore, polyvinylidene fluoride membranes were modified by electron beam-induced grafting reactions forming neutral, acidic, alkaline or zwitterionic structures on the membrane surface. The differently charged membranes were investigated regarding their surface properties using diverse analytical methods: zeta potential, static and dynamic water contact angle, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Porosimetry measurements proved that there is no pore blocking due to the modifications. Monodisperse suspensions of differently charged polystyrene beads were synthesized by a radical emulsion polymerization reaction and were used as a model fouling reagent, preventing comparability problems known from current literature. To simulate membrane fouling, different bead suspensions were filtered through the membranes. The fouling characteristics were investigated regarding permeation flux decline and concentration of model fouling reagent in filtrate as well as by SEM. By considering electrostatic interactions equal to hydrophobic interactions we developed a novel fouling test system, which enables the prediction of a membrane's fouling tendency. Electrostatic forces are dominating, especially when charged fouling reagents are present, and can help to explain fouling characteristics that cannot be explained considering the surface wettability.

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“…To reduce the problem of initial fouling, different approaches for surface hydrophilization have been investigated such as copolymerization or grafting with hydrophilic monomers [7,8,9,10,11,12,13], small organic molecules [14,15], polymers [16], enzymes [17,18]; blending using hydrophilic polymers [19,20,21,22,23,24]; incorporation of inorganic materials [25,26]; and, finally, chemical modification of the membrane polymer [27]. …”

Section: Introductionmentioning

confidence: 99%

Membrane Functionalization with Hyperbranched Polymers

2016

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Polymer membranes have been modified with hyperbranched polymers with the aim to generate a high density of hydrophilic functional groups at the membrane surface. For this purpose hyperbranched polymers containing amino, alcohol, and carboxylic acid end groups were used for membrane modification, respectively. Thus, surface potential and charges were changed significantly to result in attractive or repulsive interactions towards three different proteins (albumin, lysozyme, myoglobin) that were used to indicate membrane fouling properties. Our studies demonstrated that hydrophilization alone is not effective for avoiding membrane fouling when charged proteins are present. In contrast, electrostatic repulsion seems to be a general key factor.

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Electron beam-based functionalization of polymer membranes

Cited by 33 publications

References 5 publications

Biocatalytic Self-Cleaning Polymer Membranes

Biocatalytic Self-Cleaning Polymer Membranes

Tailoring Membrane Surface Charges: A Novel Study on Electrostatic Interactions during Membrane Fouling

Membrane Functionalization with Hyperbranched Polymers

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