Papers by Guido Kickelbick
Journal of Sol-Gel Science and Technology
Polysilsesquioxanes (PSQ) containing phenyl groups as substituents on the silicon atom can form t... more Polysilsesquioxanes (PSQ) containing phenyl groups as substituents on the silicon atom can form transparent, hard and glassy materials at room temperature, which reversibly soften when heated above the glass transition temperature. Further increase in temperature leads to irreversible curing. With this property, polyphenylsilsesquioxanes can be assigned to the so-called melting gels. In contrast to the aromatic systems, polysilsesquioxanes with alkyl groups belonging to this class of materials are not known. To identify structural differences between aryl and alkyl systems, polyalkylsilsesquioxanes (RPSQs with R = methyl, ethyl, propyl, hexyl, octyl, decyl, dodecyl, hexadecyl, and octadecyl) were synthesised by a solvent-free, acid-catalysed hydrolysis and condensation reaction of alkyltrimethoxysilanes followed by thermal treatment at 300 °C under N2 atmosphere. The influence of the alkyl chain length on the structure built and the thermally initiated further condensation reactions...
Continuous wet chemical approaches for the production of inorganic nanoparticles are important fo... more Continuous wet chemical approaches for the production of inorganic nanoparticles are important for large scale production of nanoparticles. Here we describe a bottom-up, wet chemical method applying a microjet reactor. This technique allows the separation between nucleation and growth in a continuous reactor environment. Zinc oxide (ZnO), magnetite (Fe 3 O 4), as well as brushite (CaHPO 4 •2H 2 O), particles with a small particle size distribution can be obtained continuously by using the rapid mixing of two precursor solutions and the fast removal of the nuclei from the reaction environment. The final particles were characterized by FT-IR, TGA, DLS, XRD and SEM techniques. Systematic studies on the influence of the different process parameters, such as flow rate and process temperature, show that the particle size can be influenced. Zinc oxide was obtained with particle sizes between 44 nm and 102 nm. The obtained magnetite particles have particle sizes in the range of 46 nm to 132 nm. Brushite behaves differently; the obtained particles were shaped like small plates with edge lengths between 100 nm and 500 nm.
X-ray diffraction of a polycrystalline matter causes coherently scattered intensity with more or ... more X-ray diffraction of a polycrystalline matter causes coherently scattered intensity with more or less distinct peaks. The width and shape of such a peak is caused by the setup of the radiation, the goniometer, sample preparation and intrinsic properties of the matter. The intrinsic properties of the matter, like crystallite size, microstrain, strain of other types or stacking fault densities, are also called microstructural effects. All the other effects together may be called instrumental broadening. Programs using pattern decomposition or Rietveld analysis model the width and shape of peaks by any angle dependency. Common programs, like DBWS [1], apply simple angle dependencies without physical meaning. More sophisticated programs, like FormFit [2], use separate models for instrumental broadening and microstructure and enable extensive evaluation of microstructural effects [3]. A rather new method, the fundamental parameters approach, implemented in programs like Topas [4], calcul...
Solids, 2020
Solid-state sciences continue to be one of the key pillars of scientific and technological progre... more Solid-state sciences continue to be one of the key pillars of scientific and technological progress in our society [...]
Journal of Sol-Gel Science and Technology, 2021
Silica nanoparticles with embedded fluorescent dyes represent an important class of markers for e... more Silica nanoparticles with embedded fluorescent dyes represent an important class of markers for example in biological imaging. We systematically studied the various incorporation mechanisms of fluorescent xanthene dyes in 30–40 nm silica nanoparticles. An important parameter was the interaction of the dye with the matrix material, either by weak electrostatic or strong covalent interactions, which also has implications on the stability of fluorescence and brightness of the dyes. Factors that can influence leaching of dyes such as the position of the dyes in particles and the intensity of the particle-dye interaction were investigated by using the solvatochromic effect of xanthene dyes and by stationary fluorescence anisotropy measurements. We compared uranine and rhodamine B, which were physically embedded, with modified fluorescein isothiocyanate and rhodamine B isothiocyanate, which were covalently bound to the silica matrix within a usual Stöber synthesis. Systematic leaching stu...
Surfaces, 2020
The surface functionalization of inorganic nanoparticles is an important tool for the production ... more The surface functionalization of inorganic nanoparticles is an important tool for the production of homogeneous nanocomposites. The chemical adaptation of the nano-filler surface can lead to effective weak to strong interactions between the fillers and the organic matrix. Here we present a detailed systematic study of different surface-functionalized particles in combination with a SAXS method for the systematic investigation of the interface interaction in the development of epoxy nanocomposites. We investigated the effect of surface modification of spherical SiO2 nanoparticles with 9 nm and 72 nm diameter and crystalline ZrO2 nanoparticles with 22 nm diameter on the homogeneous distribution of the fillers in diethylenetriamine (DETA) cured bisphenol-F-diglycidylether epoxy resin nanocomposites. Unmodified nanoparticles were compared with surface-modified oxides having diethylene glycol monomethyl ethers (DEG), 1,2-diols, or epoxy groups attached to the surface. The influence of su...
Dalton Transactions, 2020
Al nanoparticles have been prepared via catalytic decomposition. The influence of various reactio... more Al nanoparticles have been prepared via catalytic decomposition. The influence of various reaction parameters on their size and morphology was studied. The reaction was optimized towards short reaction times, small particle sizes, and mild conditions.
European Journal of Inorganic Chemistry, 2019
Spinel LiMn2O4 formed in a solid‐state reaction was treated with a high energy planetary ball mil... more Spinel LiMn2O4 formed in a solid‐state reaction was treated with a high energy planetary ball mill. A mechanochemical in situ surface functionalization of the nanocrystallites with a size smaller than 10 nm was achieved by addition of phenylphosphonic acid. The functionalization was proven by infrared spectroscopy and it can be shown that it prevents the formation of Mn2O3 during the milling process. Structural changes of the samples were investigated via XRD and Rietveld refinement. Mild milling conditions induce an anisotropic broadening of the reflections caused by a distribution of lattice parameters. In this first stage, we propose a structure model based on orthorhombic LiMn2O4. DSC and in situ XRD measurements also verify the presence of the orthorhombic low temperature phase. Medium milling conditions induce a change of intensities, correlated to a cation disorder. Harsher milling conditions induce the transformation to a tetragonal phase. The thermal stability of the formed...
Lithium titanates are used in various applications, such as anode materials for lithium intercala... more Lithium titanates are used in various applications, such as anode materials for lithium intercalation (Li4Ti5O12) or breeding materials in fusion reactors (Li2TiO3). Here, we report the formation of nano-crystalline lithium titanates by a mechanochemical approach and present a deeper insight into their structural characteristics by PXRD and solid-state NMR spectroscopy. The compounds were synthesized in a high energy planetary ball mill with varying milling parameters and different grinding tools. NaCl type Li2TiO3 (α-Li2TiO3) was formed by dry milling of lithium hydroxide with titania (rutile or anatase) and by a milling induced structure transformation of monoclinic β Li2TiO3 or spinel type Li4Ti5O12. Heating of mechanochemical prepared α Li2TiO3 induces a phase transformation to the monoclinic phase similar to hydrothermal reaction products, but a higher thermal stability was observed for the mechanochemical formed product. Microstructure and crystallographic str...
Sustainable Energy & Fuels, 2017
The MicroJet reactor was used to manufacture polyorganosilsesquioxane beads which were pyrolyzed ... more The MicroJet reactor was used to manufacture polyorganosilsesquioxane beads which were pyrolyzed to obtain silicon oxycarbides and chlorinated to obtain carbide-derived carbon for supercapacitor application.
Dalton Transactions, 2017
Octaaminospherosilicates have been synthesized using hydrogenation over Pd/C and were reacted in ... more Octaaminospherosilicates have been synthesized using hydrogenation over Pd/C and were reacted in situ with propyl isocyanate to give octafunctional hydrogen bond bearing spherosilicates [CnH2n(NHCONH)C3H7]; (n = 4, 5, 6, 11).
Inorganics, 2014
Continuous wet chemical approaches for the production of inorganic nanoparticles are important fo... more Continuous wet chemical approaches for the production of inorganic nanoparticles are important for large scale production of nanoparticles. Here we describe a bottom-up, wet chemical method applying a microjet reactor. This technique allows the separation between nucleation and growth in a continuous reactor environment. Zinc oxide (ZnO), magnetite (Fe 3 O 4), as well as brushite (CaHPO 4 •2H 2 O), particles with a small particle size distribution can be obtained continuously by using the rapid mixing of two precursor solutions and the fast removal of the nuclei from the reaction environment. The final particles were characterized by FT-IR, TGA, DLS, XRD and SEM techniques. Systematic studies on the influence of the different process parameters, such as flow rate and process temperature, show that the particle size can be influenced. Zinc oxide was obtained with particle sizes between 44 nm and 102 nm. The obtained magnetite particles have particle sizes in the range of 46 nm to 132 nm. Brushite behaves differently; the obtained particles were shaped like small plates with edge lengths between 100 nm and 500 nm.
European Journal of Inorganic Chemistry, 2014
Octafunctional spherosilicates were used to prepare self‐healing hybrid materials. The hydrosilat... more Octafunctional spherosilicates were used to prepare self‐healing hybrid materials. The hydrosilation of the octakis(hydridodimethylsiloxy)‐substituted spherosilicate with furfuryl allyl ether generates an inorganic nano‐building‐block that is used to formulate various self‐healing hybrid materials based on a reversible Diels–Alder reaction. Curing with a molecular bismaleimide results in a hard, glassy but reversibly cross‐linkable hybrid material. The reversibility of the curing mechanism allows the preparation of films with a heated press, which also opens the possibility to process the materials by injection molding. Substitution of the molecular cross‐linker with an oligomeric poly(dimethylsiloxane) bismaleimide results in an elastomeric material. The kinetics of the Diels–Alder reaction upon cooling after a retro‐Diels–Alder reaction are mainly controlled by the mobility of the cross‐linker within the system.
Journal of Materials Chemistry C, 2013
New J. Chem., 2014
Surface functionalized titania particles are obtained using a high energy planetary ball mill.
Acta Crystallographica Section E Structure Reports Online, 2007
DOI to the publisher's website. • The final author version and the galley proof are versions of t... more DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
Acta Crystallographica Section E Structure Reports Online, 2009
Acta Crystallographica Section E Structure Reports Online, 2002
Acta Crystallographica Section E Structure Reports Online, 2002
Acta Crystallographica Section E Structure Reports Online, 2002
Uploads
Papers by Guido Kickelbick