61 research outputs found
In situâDirected Growth of Organic Nanofibers and Nanoflakes: Electrical and Morphological Properties
Organic nanostructures made from organic molecules such as para-hexaphenylene (p-6P) could form nanoscale components in future electronic and optoelectronic devices. However, the integration of such fragile nanostructures with the necessary interface circuitry such as metal electrodes for electrical connection continues to be a significant hindrance toward their large-scale implementation. Here, we demonstrate in situâdirected growth of such organic nanostructures between pre-fabricated contacts, which are sourceâdrain gold electrodes on a transistor platform (bottom-gate) on silicon dioxide patterned by a combination of optical lithography and electron beam lithography. The dimensions of the gold electrodes strongly influence the morphology of the resulting structures leading to notably different electrical properties. The ability to control such nanofiber or nanoflake growth opens the possibility for large-scale optoelectronic device fabrication
Patterning of light-emitting conjugated polymer nanofibres.
Organic materials have revolutionized optoelectronics by their processability, flexibility and low cost, with application to light-emitting devices for full-colour screens, solar cells and lasers. Some low-dimensional organic semiconductor structures exhibit properties resembling those of inorganics, such as polarized emission and enhanced electroluminescence. One-dimensional metallic, III-V and II-VI nanostructures have also been the subject of intense investigation as building blocks for nanoelectronics and photonics. Given that one-dimensional polymer nanostructures, such as polymer nanofibres, are compatible with sub-micrometre patterning capability and electromagnetic confinement within subwavelength volumes, they can offer the benefits of organic light sources to nanoscale optics. Here we report on the optical properties of fully conjugated, electrospun polymer nanofibres. We assess their waveguiding performance and emission tuneability in the whole visible range. We demonstrate the enhancement of the fibre forward emission through imprinting periodic nanostructures using room-temperature nanoimprint lithography, and investigate the angular dispersion of differently polarized emitted light
Nature's lessons in design: nanomachines to scaffold, remodel and shape membrane compartments.
Compartmentalisation of cellular processes is fundamental to regulation of metabolism in Eukaryotic organisms and is primarily provided by membrane-bound organelles. These organelles are dynamic structures whose membrane barriers are continually shaped, remodelled and scaffolded by a rich variety of highly sophisticated protein complexes. Towards the goal of bottom-up assembly of compartmentalised protocells in synthetic biology, we believe it will be important to harness and reconstitute the membrane shaping and sculpting characteristics of natural cells. We review different in vitro membrane models and how biophysical investigations of minimal systems combined with appropriate theoretical modelling have been used to gain new insights into the intricate mechanisms of these membrane nanomachines, paying particular attention to proteins involved in membrane fusion, fission and cytoskeletal scaffolding processes. We argue that minimal machineries need to be developed and optimised for employment in artificial protocell systems rather than the complex environs of a living organism. Thus, well-characterised minimal components might be predictably combined into functional, compartmentalised protocellular materials that can be engineered for wide-ranging applications
Nanostructure of Fully Injectable HydrazoneâThiosuccinimide Interpenetrating Polymer Network Hydrogels Assessed by Small-Angle Neutron Scattering and dSTORM Single-Molecule Fluorescence Microscopy
Herein,
we comprehensively investigate the internal morphology
of fully injectable interpenetrating networks (IPNs) prepared via
coextrusion of functionalized precursor polymer solutions based on
thermoresponsive polyÂ(<i>N</i>-isopropylacrylamide) (PNIPAM)
and nonthermoresponsive polyÂ(vinyl pyrrolidone) (PVP) by reactive
mixing using kinetically orthogonal hydrazone and thiosuccinimide
cross-linking mechanisms. Small-angle neutron scattering, probing
both the full IPN as well as the individual constituent networks of
the IPN using index-matching, suggests a partially mixed internal
structure characterized by PNIPAM-rich domains entrapped in a clustered
PVP-rich phase. This interpretation is supported by super-resolution
fluorescence microscopy (direct stochastic optical reconstruction
microscopy) measurements on the same gels on a different length scale,
which show both the overall phase segregation typical of an IPN as
well as moderate mixing of PNIPAM into the PVP-rich phase. Such a
morphology is consistent with the kinetics of both gelation and phase
separation in this in situ gelling system, in which gelation effectively
traps a fraction of the PNIPAM in the PVP phase prior to full phase
separation; by contrast, such interphase mixing is not observed in
semi-IPN control hydrogels. This knowledge has significant potential
for the design of an injectable hydrogel with internal morphologies
optimized for particular biomedical applications
Visualising recalcitrance by colocalisation of cellulase, lignin and cellulose in pretreated pine biomass using fluorescence microscopy
Parylene peel-off arrays to probe the role of cellâcell interactions in tumour angiogenesis
Fluorescent Labeling and Characterization of Cellulose Nanocrystals with Varying Charge Contents
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