Pyrolyzed polysiloxane membranes with tailorable hydrophobicity, porosity and high specific surface area

Prenzel, Torsten; Wilhelm, Michaela; Rezwan, Kurosch

doi:10.1016/j.micromeso.2012.10.014

Cited by 38 publications

(36 citation statements)

References 37 publications

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“…As already mentioned in the SEM part, the macroscopic morphology of the not pyrolyzed samples and the pyrolyzed samples are identical. In general it can be observed that the MEBC pyrolyzed at 600 • C generates higher SSA than the samples pyrolyzed at 500 • C. The explanation for that is the higher decomposition degree at 600 • C which results in more micropores and in this way in higher SSA [7][8][9]26,27]. Fig.…”

Section: Characterization At the Microscopic Length Scalementioning

confidence: 86%

“…adsorbent materials or carrier materials for catalysis, materials with controllable surface characteristics in terms of hydrophobicity/hydrophilicity and porosity on different length scales (micro-/meso-/macro) are needed. These characteristics can be adjusted by using Ceramers with different pyrolysis temperatures, precursor compositions and reaction conditions [7][8][9]. Additionally, monoliths with a sufficient mechanical stability and adjustable porosity are required for potential applications like adsorbents, filters or functional catalysts.…”

Section: Introductionmentioning

confidence: 99%

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Surfactant assisted syntheses of monolithic hybrid ceramics with hierarchical porosity

Schlüter¹,

Wilhelm²,

Rezwan³

2015

Journal of the European Ceramic Society

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Section: Characterization At the Microscopic Length Scalementioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Surfactant assisted syntheses of monolithic hybrid ceramics with hierarchical porosity

Schlüter¹,

Wilhelm²,

Rezwan³

2015

Journal of the European Ceramic Society

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“…[12] This effect is reported in the literature mostly to develop polysiloxane based membranes or thin films with gradient surface characteristics from hydrophobic to hydrophilic by varying the content of methyl-or phenyl-groups locally or by pyrolyzing the samples with a temperature gradient. [12][13][14][15][16] In this work, we describe a method to produce open cellular alumina foams with varying surface characteristics from hydrophobic to hydrophilic by coating with a filler-loaded pre-ceramic polymer system and pyrolyzing at different temperatures under inert gas atmosphere. Subsequently, the foams were tested in a multi-phase mixing process, since the combination of the modified surface characteristics of the foam structures and their excellent tortuosity might be useful as reactor installations in multiphase systems for dispersing immiscible liquid phases.…”

Section: Introductionmentioning

confidence: 99%

Tailored Surface Properties of Ceramic Foams for Liquid Multiphase Reactions

et al. 2017

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Open cellular ceramic foams are prepared using the replica method. In a second step, these foams are coated with a pre-ceramic or polymer-derived ceramic coating, respectively. Polymer-to-ceramic transformation is studied by SEM with respect to the microstructure, functional groups are characterized by Raman microscopy, density and porosity are determined by pycnometer measurements as well as the surface free energy by means of contact angle measurements. By pyrolysis at different temperatures between 403 and 1273 K, the surface wettability is adjusted in a wide range from hydrophilic to hydrophobic due to the release of organic groups from the pre-ceramic polymers in terms of polymer-toceramic transformation. Coated foams are tested in a new potential application: as reactor internals to increase the liquid-liquid interface area in a homogeneously catalyzed multiphase system. As model reaction, a reactive extraction of an organic dye was used and the influence of the surface energy of the foam on the phase dispersion/reaction rate is discussed. The coated foams are able to increase the reaction rate to an extent depending on the surface wettability.

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“…Micropores are responsible for high specific surface areas. Beyond controlled porosity it is also possible to adjust the surface characteristics by precursor composition and the pyrolysis temperature [19,20]. Increased permeability for CO 2 and selectivity over H 2 , N 2 and O 2 was observed with increasing polarity in the case of polyethylene glycol [21].…”

Section: Introductionmentioning

confidence: 99%

“…It is possible to generate monolithic polysiloxane membranes functionalized with organic groups throughout the membrane without post synthetic functionalization [20,27]. The material properties can be controlled by converting of a polymeric material to a hybrid ceramic at low temperatures, thereby optimizing the properties for gas adsorption and separation processes.…”

Section: Introductionmentioning

confidence: 99%