The surface wetting of five biopolymers, used as coating materials for a plastic film, was monito... more The surface wetting of five biopolymers, used as coating materials for a plastic film, was monitored over a span of 8 min by means of the optical contact angle technique. Because most of the total variation was observed to occur during the first 60 s, we decided to focus on this curtailed temporal window. Initial contact angle values (θ(0)) ranged from ∼91° for chitosan to ∼30° for pullulan. However, the water drop profile began to change immediately following drop deposition for all biocoatings, confirming that the concept of water contact angle equilibrium is not applicable to most biopolymers. First, a three-parameter decay equation [θ(t) = θ(0) exp(kt(n))] was fit to the experimental contact angle data to describe the kinetics of the contact angle change for each biocoating. Interestingly, the k constant correlated well with the contact angle evolution rate and the n exponent seemed to be somehow linked to the physicochemical phenomena underlying the overall kinetics process. Second, to achieve a reliable description of droplet evolution, the contact angle (CA) analysis was coupled with image analysis (IA) through a combined geometric/trigonometric approach. Absorption and spreading were the key factors governing the overall mechanism of surface wetting during the 60 s analysis, although the individual quantification of both phenomena demonstrated that spreading provided the largest contribution for all biopolymers, with the only exception of gelatin, which showed two quasi-equivalent and counterbalancing effects. The possible correlation between these two phenomena and the topography of the biopolymer surfaces are then discussed on the basis of atomic force microscopy analyses.
Since its introduction about 20 years ago, two-photon microscopy has become a widespread tool in ... more Since its introduction about 20 years ago, two-photon microscopy has become a widespread tool in high-spatial resolution imaging, especially of biological tissues, because of the quadratic dependence of absorption on the excitation intensity, which confines fluorescence and ...
» View Full Text: Acrobat PDF (12 KB) * * Note that full-text PDFs from conferences typically con... more » View Full Text: Acrobat PDF (12 KB) * * Note that full-text PDFs from conferences typically contain 1-3 pages of content, some or all of which might be an abstract, summary, or miscellaneous items. ... Plasmonic modes of single-crystalline gold nanoparticle dimers with ultrasmall ...
... Original Paper. Recent developments in linear and nonlinear near-field microscopy on single p... more ... Original Paper. Recent developments in linear and nonlinear near-field microscopy on single plasmonic nanoparticles. Lamberto Duò,; Paolo Biagioni,; Marco Finazzi. Article first published online: 18 JUN 2010. DOI: 10.1002/pssb.200983939. ...
Abstract: suitably shaped metal nanostructures act as resonant optical antennas that efficiently ... more Abstract: suitably shaped metal nanostructures act as resonant optical antennas that efficiently collect light and confine it to a subwavelength volume. Vice versa, light emission from nano volumes can be enhanced by coupling to antenna structures. We give a short introduction to ...
One of the major advantages offered by optics is the possibility to directly visualize the wave p... more One of the major advantages offered by optics is the possibility to directly visualize the wave packet dynamics in coordinate space. However, direct far-field imaging of field distributions in the photonic structure is prevented by the evanescent nature of the fields along the ...
The surface wetting of five biopolymers, used as coating materials for a plastic film, was monito... more The surface wetting of five biopolymers, used as coating materials for a plastic film, was monitored over a span of 8 min by means of the optical contact angle technique. Because most of the total variation was observed to occur during the first 60 s, we decided to focus on this curtailed temporal window. Initial contact angle values (θ(0)) ranged from ∼91° for chitosan to ∼30° for pullulan. However, the water drop profile began to change immediately following drop deposition for all biocoatings, confirming that the concept of water contact angle equilibrium is not applicable to most biopolymers. First, a three-parameter decay equation [θ(t) = θ(0) exp(kt(n))] was fit to the experimental contact angle data to describe the kinetics of the contact angle change for each biocoating. Interestingly, the k constant correlated well with the contact angle evolution rate and the n exponent seemed to be somehow linked to the physicochemical phenomena underlying the overall kinetics process. Second, to achieve a reliable description of droplet evolution, the contact angle (CA) analysis was coupled with image analysis (IA) through a combined geometric/trigonometric approach. Absorption and spreading were the key factors governing the overall mechanism of surface wetting during the 60 s analysis, although the individual quantification of both phenomena demonstrated that spreading provided the largest contribution for all biopolymers, with the only exception of gelatin, which showed two quasi-equivalent and counterbalancing effects. The possible correlation between these two phenomena and the topography of the biopolymer surfaces are then discussed on the basis of atomic force microscopy analyses.
Since its introduction about 20 years ago, two-photon microscopy has become a widespread tool in ... more Since its introduction about 20 years ago, two-photon microscopy has become a widespread tool in high-spatial resolution imaging, especially of biological tissues, because of the quadratic dependence of absorption on the excitation intensity, which confines fluorescence and ...
» View Full Text: Acrobat PDF (12 KB) * * Note that full-text PDFs from conferences typically con... more » View Full Text: Acrobat PDF (12 KB) * * Note that full-text PDFs from conferences typically contain 1-3 pages of content, some or all of which might be an abstract, summary, or miscellaneous items. ... Plasmonic modes of single-crystalline gold nanoparticle dimers with ultrasmall ...
... Original Paper. Recent developments in linear and nonlinear near-field microscopy on single p... more ... Original Paper. Recent developments in linear and nonlinear near-field microscopy on single plasmonic nanoparticles. Lamberto Duò,; Paolo Biagioni,; Marco Finazzi. Article first published online: 18 JUN 2010. DOI: 10.1002/pssb.200983939. ...
Abstract: suitably shaped metal nanostructures act as resonant optical antennas that efficiently ... more Abstract: suitably shaped metal nanostructures act as resonant optical antennas that efficiently collect light and confine it to a subwavelength volume. Vice versa, light emission from nano volumes can be enhanced by coupling to antenna structures. We give a short introduction to ...
One of the major advantages offered by optics is the possibility to directly visualize the wave p... more One of the major advantages offered by optics is the possibility to directly visualize the wave packet dynamics in coordinate space. However, direct far-field imaging of field distributions in the photonic structure is prevented by the evanescent nature of the fields along the ...
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