Patrick Kempe

Twin Polymerization at Spherical Hard Templates: An Approach to Size‐Adjustable Carbon Hollow Spheres with Micro‐ or Mesoporous Shells

Kitset hollow spheres: The combination of twin polymerization with hard templates makes hollow carbon spheres (HCSs) with tailored properties easily accessible. The thickness and pore texture of the HCS shells and also the diameter of the spherical cavity can be varied. The application potential of synthesized HCS is substantiated by an excellent cycling stability of lithium-sulfur batteries.

Selective ring opening of 4H-1,3,2-benzodioxasiline twin monomers

4H-1,3,2-Benzodioxasilines represent a class of monomers, which are suitable for the recently developed concept of twin polymerization. Relating to the prediction of quantum chemical calculations we are now able to confirm the results for the first step of the reaction: the selective ring opening of 4H-1,3,2-benzodioxasilines. An electrophilic attack of iodotrimethylsilane leads firstly to a bond cleavage at the oxymethylene group and not at the more stable Si–O–aryl bond, yielding ring-opened species.

The Controlled Synthesis of Carbon Tubes and Rods by Template-Assisted Twin Polymerization

The application of porous carbon is versatile. It is used for high-performance catalyst support, electrode material in batteries, and gas storage. In each of these application fields nanostructuring improves the material properties. Supercapacitors store a high energy density. Exactly adapted carbon structures increase the life of lithium batteries and protect catalysts with increasing reaction rate and selectivity. Most of porous carbon materials have a spherical shape. To the best of our knowledge, there is no procedure to synthesize nanostructured cylindrical porous carbon systematically. Here, template glass fibres and SiO2-tubes were modified with nanostructured SiO2/phenolic resin and SiO2/poly(furfuryl alcohol) layers by surface twin polymerization (TP) of 2,2′-spirobi[4H-1,3,2-benzodioxasiline] and tetrafurfuryloxysilane. Afterwards the SiO2/polymer layer on the template is thermally transformed into a defect-free nanostructured SiO2/carbon layer. After completely removing the SiO2 components microporous carbon tubes or rods are finally achieved. The diameters of the carbon rods and the inner as well as the outer diameter of the carbon tubes are adjustable according to the shape and size of the template. Thus, a huge variety of microporous carbon materials can be easily produced by template-assisted TP.