New Hybrid Inorganic/Organic Block Copolymers as Templates for the Formation of Mesostructured Materials
- PDF / 176,188 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 91 Downloads / 193 Views
New Hybrid Inorganic/Organic Block Copolymers as Templates for the Formation of Mesostructured Materials Guido Kickelbick, Josef Bauer, Nicola Hüsing Institut für Anorganische Chemie, Technische Universität Wien, Getreidemarkt 9, A-1060 Wien, AUSTRIA ABSTRACT Amphiphilic block copolymers were prepared with poly(dimethylsiloxane) (PDMS) as the hydrophobic unit. The hydrophilic block was composed of either a poly(ethylene oxide) or a functionalized polysiloxane unit. The polymer based on polysiloxane blocks only, represents one of the first examples of a new class of surfactants with a purely inorganic Si-O backbone. Beside their potential use as templates for the synthesis of mesostructured inorganic materials, these new polymers offer the possibility of being transformed into porous mesostructured silica-based material by controlled pyrolysis. INTRODUCTION The tailoring of micro- and mesostructures is one of the major goals in materials design. Especially the deliberate construction of hybrid organic-inorganic composites and their calcination products, the corresponding porous inorganic materials, is of outstanding interest in fields like membrane or sensor synthesis. The general way to do this is by using template molecules, especially compounds that are able to induce order due to a self-assembling behavior [1]. Ionic surfactants like cetyltrimethylammonium bromide (CTAB), are typical representatives of such templates [2]. Meanwhile, a lot of different compounds like non-ionic surfactants, inorganic and organic particles, liquid crystalline molecules and mixtures of these systems are used to tailor the mesostructure of inorganic and organic materials [3]. Although this field is rapidly growing, systematic studies of the influence of properties of the templating agents as well as the processing parameters on the structures are rare. Especially non-ionic block copolymer surfactants offer the possibility to investigate the influence of different properties on the templating mechanism such as the polarity of the blocks, incorporation of functional groups, size, shape, etc. Most block copolymers applied in templating processes are commercially available. Therefore, studies carried out based on these systems were limited on their availability. Typical examples are shown in Table I. Apart from the restricted availability of amphiphilic block copolymers commercial products are sometimes not pure and have low polydispersities. Our goal is the synthesis of new amphiphilic block copolymers in which properties like block length, polarity and functionalization can be controlled over a wide range for the purpose to study the influence of these parameters in the templated formation of inorganic materials. This can only be achieved by controlled polymerization techniques, such as for example controlled radical or ring
CC3.1.1 Downloaded from https://www.cambridge.org/core. University of Arizona, on 27 Jul 2018 at 07:44:09, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.
Data Loading...
