322 research outputs found
Cholesteric liquid crystalline polymer networks as optical sensors
No full textIn the past decade, chiral nematic liquid crystals (LCs) have emerged as an attractive material for the development of stimuli-responsive systems (White et al. 2010; Ge and Yin 2011; Fenzl et al. 2014; Mulder et al. 2014; Stumpel et al. 2014). Due to the periodic alteration of their refractive indices, they act as one-dimensional photonic structures and reect circularly polarized light of same handedness. The reection of light is governed by Bragg’s law: λ θb = nP cos where λb is the wavelength of Bragg reection, n is the average refractive index, and P is the length of the helical pitch. The pitch of a chiral nematic is dened as the length traversed by the molecular director nˆ on 360° rotation (Figure 4.1a). It is inversely proportional to the concentration [C] as well as the helical twisting power
Fluorene benzothiadiazole co-oligomer based aqueous self-assembled nanoparticles
No full textSelf-assembled pi -conjugated nanoparticles with tunable optical characteristics are appealing for sensing and imaging applications due to their intrinsic fluorescence, supramolecular organization and dynamics. Here we report on the facile synthesis of fluorene benzothiadiazole co-oligomers in which structural backbone alterations induce bathochromically shifted optical characteristics. Moreover, the nature of the oligomer side-chains revealed the role of bulkiness and polarity on the optical and self-assembly behavior. Co-assemblies were prepared that showed energy transfer between the different oligomers which allows for tuning of the emission color. These compounds thus extend the pi -conjugated-oligomer toolbox from which nanoparticles can be prepared with tailored physicochemical properties that may result in supramolecular materials for biosensing
Organization and visualization of self-assembled pi-conjugated oligo(p-phenylene vinylene)s
No full text
De supramoleculaire aanpak in de nanotechnologie
No full textVorig jaar werd door NWO een VIDI-voorstel gehonoreerd om op nanometergrootte elektrische componenten te maken. Bij dit voorstel was niet voor een moleculaire, maar voor een zogenaamde supramoleculaire aanpak gekozen. Bij deze strategie worden organische halfgeleiders zodanig ontworpen dat ze eendimensionale kristallen vormen met een lengte van honderd nanometer. Het idee is om deze draden tussen elektrodes te brengen om zo miniatuur elektro-optische apparatuur te construeren
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