Discovering Synthesis Routes to Hexagonally Ordered Mesoporous Niobium Nitrides Using Poloxamer/Pluronics Block Copolymers

Extracellular laccase produced by the wood-rotting fungus Cerrena unicolor was immobilised covalently on the mesostructured siliceous foam (MCF) and three hexagonally ordered mesoporous silicas (SBA-15) with different pore sizes. The enzyme was attached covalently via glutaraldehyde (GLA) or by simple adsorption and additionally crosslinked with GLA. The experiments indicated that laccase bound by covalent attachment remains very active and stable. The best biocatalysts were MCF and SBA-15 with Si-F moieties on their surface. Thermal inactivation of immobilised and native laccase at 80°C showed a biphasic-type activity decay, that could be modelled with 3- parameter isoenzyme model. It appeared that immobilisation did not significantly change the mechanism of activity loss but stabilised a fraction of a stable isoform. Examination of time needed for 90% initial activity loss revealed that immobilisation prolonged that time from 8 min (native enzyme) up to 155 min (SBA-15SF).

Download Full-text

Rheology of Phase Separated Block Copolymer Melts

MRS Proceedings ◽

10.1557/proc-177-245 ◽

1989 ◽

Vol 177 ◽

Author(s):

H. Henning Winter ◽

Faith A. Morrison

Keyword(s):

Block Copolymer ◽

Block Copolymers ◽

Single Crystals ◽

Domain Structure ◽

Shear Direction ◽

Cylindrical Domain ◽

Global Order ◽

Copolymer Melts ◽

Cylindrical Domains ◽

Hexagonally Ordered

Flow can transfer the microphase separated morphology of block copolymers into a state of global order. For tri-block copolymers with cylindrical domains, this has been demonstrated by Folkes et al. (1973) and Hadziioannou et al. (1979). who established the existence of ‘single crystals’ of hexagonally ordered cylinders with uniform director throughout a sheared sample. The director is aligned with the shear direction. In this study, we investigate the flow induced ordering of cylindrical domain structure at increasing levels of shear.

Download Full-text

Metallic Ni nanoparticles confined in hexagonally ordered mesoporous silica material

Chemical Communications ◽

10.1039/b411074a ◽

2005 ◽

pp. 348 ◽

Cited By ~ 17

Author(s):

Katsutoshi Yamamoto ◽

Yoji Sunagawa ◽

Hideyuki Takahashi ◽

Atsushi Muramatsu

Keyword(s):

Mesoporous Silica ◽

Ordered Mesoporous Silica ◽

Ni Nanoparticles ◽

Mesoporous Silica Material ◽

Silica Material ◽

Ordered Mesoporous ◽

Hexagonally Ordered

Download Full-text

Self-assembled ordered mesoporous metals

Pure and Applied Chemistry ◽

10.1351/pac-con-08-09-12 ◽

2009 ◽

Vol 81 (1) ◽

pp. 73-84 ◽

Cited By ~ 20

Author(s):

Scott C. Warren ◽

Ulrich Wiesner

Keyword(s):

Information Processing ◽

Block Copolymers ◽

Energy Conversion ◽

Self Assembly ◽

Historical Development ◽

The Self ◽

Entry Point ◽

Physical Models ◽

Length Scale ◽

Ordered Mesoporous

Control over the structure of metals at the mesoscale (2-50 nm) is crucial for emerging applications such as energy conversion, sensing, and information processing. The self-assembly of nanoparticles with block copolymers provides a natural entry point to materials of this length scale. The field's historical development, relevant physical models, and recent results are presented.

Download Full-text