Precise determination of the elastic properties of soft condensed matter at the nanoscale is impo... more Precise determination of the elastic properties of soft condensed matter at the nanoscale is important in many situations, from substrate characterization to cancer cell differentiation. When measuring these properties at the nanoscale through contact mechanics, adhesive effects dominate the interaction and prevent obtaining quantitative results. As a solution to this problem, a non-contact measuring mode in liquid has previously been developed for the surface force apparatus (SFA). [1] Advantages of this technique are the non-invasiveness of the measurement and the prevention of probe contamination. SFA measurements are however limited by the macroscopic size of the probe, requiring homogeneous samples and introducing substrate effects in soft films thinner than 300 nm. To surpass these limits our project has moved the technique to the AFM platform where microscale probes can be utilized, allowing for lateral resolution below the micron scale. In contrast to conventional AFM, the t...
Because of capillary condensation, water droplets appear in nano/micropores. The large associated... more Because of capillary condensation, water droplets appear in nano/micropores. The large associated surface interactions can deeply influence macroscopic properties as in granular media. We report that dynamical properties of such nanobridge dramatically change when probed at different time scales. Using a novel AFM mode, the Force Feedback Microscopy, the gap between the nano-‐‑ tip and the surface is continuously varied, and we observe this change in the simultaneous measurements, at different frequencies, of the stiffness G'(N/m), the dissipative coefficient G " (kg/sec) together with the static force. As the measuring time approaches the microsecond , the liquid droplet exhibits a large positive stiffness (it is small and negative in the long time limit). Although clearly controlled by surface effects , it compares to the stiffness of a solid nanobridge with a 1 GigaPa Young modulus. We argue that as evaporation and condensation gradually lose efficiency , the contact li...
Extended Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems
Figure 1: Overview of the grip pen sensing tool. Left.The hardware grip sensing tool is attached ... more Figure 1: Overview of the grip pen sensing tool. Left.The hardware grip sensing tool is attached to a regular pen. A sensitive matrix is wrapped around the body of the pen, and data processing algorithms are performed to detect grasp posture.
Proceedings of the 18th ACM International Conference on Interaction Design and Children
This PhD project is multidisciplinary, at the intersection of Early Childhood Education, Design, ... more This PhD project is multidisciplinary, at the intersection of Early Childhood Education, Design, and Human-Computer Interaction. The PhD goal aim at developing new approaches for early childhood education focusing on the role of body in the learning process. We leverage digital tangible and interactive technologies to develop specific scenarios that are evaluated in preschools. Our work proposes novel paradigms and uses of digital technologies currently not found in typical preschool environments.
The invention relates to an optical device for interferometric analysis of the surface of an obje... more The invention relates to an optical device for interferometric analysis of the surface of an object condition (2), comprising a light source (1); an optical fiber (42) adapted to receive the incident light wave to transmit it to the object (2); a detector (9) adapted to detect a combination of a light wave (45) reflected by the optical fiber and a light wave (46) reflected by the object; and wherein the optical fiber (42) has a free end shaped cone having an angle at the top between 15 and 25 degrees, the tip of the cone having dimensions of less than 50 x 50 nm, and the tip of the cone is disposed , in use, at a distance from the surface of the object between 5 and 50 .mu.m.
Five fold i-AlPdMn surface prepared under UHV by ion bombardment and annealing was so far conside... more Five fold i-AlPdMn surface prepared under UHV by ion bombardment and annealing was so far considered to be bulk terminated. This result was substantially based on a quantitative LEED analyses [1]. Analysis of the specular rod in a X ray diffraction experiment at grazing incidence supported this result [2]. We present a new study of this surface by high resolution X ray diffraction at normal incidence. In this Bragg configuration the diffraction peak 18 – 29 for instance is at a photon energy of 2.873keV, the 72 – 116 reflection at 5.725keV. This results in an analyzed thickness of the sample surface of a few micrometers.The surface was cleaned by ion bombardment. During annealing (T≅880K), we clearly observed the progressive disappearance of the initial Bragg peak characteristic of the as cast bulk sample. Conversely a new Bragg peak grows at an energy position shifted by 1eV compared to the position of the original Bragg peak. This is a clear signature for an irreversible structura...
In this article, we measure the viscous damping G″, and the associated stiffness G′, of a liquid ... more In this article, we measure the viscous damping G″, and the associated stiffness G′, of a liquid flow in sphere-plane geometry over a large frequency range. In this regime, the lubrication approximation is expected to dominate. We first measure the static force applied to the tip. This is made possible thanks to a force feedback method. Adding a sub-nanometer oscillation of the tip, we obtain the dynamic part of the interaction with solely the knowledge of the lever properties in the experimental context using a linear transformation of the amplitude and phase change. Using a Force Feedback Microscope (FFM), we are then able to measure simultaneously the static force, the stiffness, and the dissipative part of the interaction in a broad frequency range using a single AFM probe. Similar measurements have been performed by the Surface Force Apparatus (SFA) with a probe radius hundred times bigger. In this context, the FFM can be called nano-SFA.
In the past few years the heteroepitaxy on Si substrates of the semiconducting orthorhombic disil... more In the past few years the heteroepitaxy on Si substrates of the semiconducting orthorhombic disilicide β-FeSi2 has been extensively studied since it might be of potential applications in integrated optoelectronic devices, due to its optical gap measured closely to 0.85 eV. During the course of these investigations several unexpected pseudomorphic phases of ultra thin FeSi2 layers have been observed on top of the Si substrates. The growth of these phases and their physicochemical properties have been investigated with a large variety of preparation methods and surface techniques. A particular attention will be paid to the mechanisms of stabilization of such metastable phases due to their epitaxy on Si substrates, and to their transition, both electronic and structural, towards the β-FeSi2 phase. Recent findings concerning the growth at low temperature of the α-FeSi2 phase will also be discussed since it might shed light on the hierarchy of these phase transitions.
An overview of different strategies recently proposed to tune, by mechanical actuation or phase t... more An overview of different strategies recently proposed to tune, by mechanical actuation or phase transition, the near-field heat transfer between two media is presented. These results open the way to an efficient active management of heat transfer at nanoscale.
Atomic Force Microscopy (AFM) conventional static force curves and Force Feedback Microscopy (FFM... more Atomic Force Microscopy (AFM) conventional static force curves and Force Feedback Microscopy (FFM) force curves acquired with the same cantilever at the solid/air and solid/liquid interfaces are here compared. The capability of the FFM to avoid the jump to contact leads to the complete and direct measurement of the interaction force curve, including the attractive short-range van der Waals and chemical contributions. Attractive force gradients five times higher than the lever stiffness do not affect the stability of the FFM static feedback loop. The feedback loop keeps the total force acting on the AFM tip equal to zero, allowing the use of soft cantilevers as force transducers to increase the instrumental sensitivity. The attractive interactions due to the nucleation of a capillary bridge at the native oxide silicon/air interface or due to a DLVO interaction at the mica/deionized water interface have been measured. This set up, suitable for measuring directly and quantitatively interfacial forces, can be exported to a SFA (Surface Force Apparatus).
It has been predicted theoretically that for distances smaller than the peak wavelength of the bl... more It has been predicted theoretically that for distances smaller than the peak wavelength of the blackbody spectrum, radiative heat transfer can be increased by the contribution of evanescent waves [1]. These effects have already been observed but a quantitative comparison is still missing. We measure the heat flux between a sphere and a plate as a function of the sphere-plate distance. We find a good agreement between the experimental and theoretical results . Particularly, the distance dependence is well reproduced by the theory in a large range of gap widths: 50nm-2μm.
ABSTRACT Nanotechnology has been touted as the next ‘industrial revolution’ of our modern age. In... more ABSTRACT Nanotechnology has been touted as the next ‘industrial revolution’ of our modern age. In order for successful research, development, and social discourses to take place in this field, education research is needed to inform the development of standards, course development, and workforce preparation. In addition, there is a growing need to educate citizens and students about risks, benefits, and social and ethical issues related to nanotechnology. This position paper describes the advancements that have been made in nanoscale science and nanotechnology, and the challenges that exist to educate students and the public about critical nanoscience concepts. This paper reviews the current research on nanotechnology education including curricula, educational programs, informal education, and teacher education. Furthermore, the unique risks, benefits and ethics of these unusual technological applications are described in relation to nanoeducation goals. Finally, we outline needed future research in the areas of nanoscience content, standards and curricula, nanoscience pedagogy, teacher education, and the risks, benefits, and social and ethical dimensions for education in this emerging field.
Precise determination of the elastic properties of soft condensed matter at the nanoscale is impo... more Precise determination of the elastic properties of soft condensed matter at the nanoscale is important in many situations, from substrate characterization to cancer cell differentiation. When measuring these properties at the nanoscale through contact mechanics, adhesive effects dominate the interaction and prevent obtaining quantitative results. As a solution to this problem, a non-contact measuring mode in liquid has previously been developed for the surface force apparatus (SFA). [1] Advantages of this technique are the non-invasiveness of the measurement and the prevention of probe contamination. SFA measurements are however limited by the macroscopic size of the probe, requiring homogeneous samples and introducing substrate effects in soft films thinner than 300 nm. To surpass these limits our project has moved the technique to the AFM platform where microscale probes can be utilized, allowing for lateral resolution below the micron scale. In contrast to conventional AFM, the t...
Because of capillary condensation, water droplets appear in nano/micropores. The large associated... more Because of capillary condensation, water droplets appear in nano/micropores. The large associated surface interactions can deeply influence macroscopic properties as in granular media. We report that dynamical properties of such nanobridge dramatically change when probed at different time scales. Using a novel AFM mode, the Force Feedback Microscopy, the gap between the nano-‐‑ tip and the surface is continuously varied, and we observe this change in the simultaneous measurements, at different frequencies, of the stiffness G'(N/m), the dissipative coefficient G " (kg/sec) together with the static force. As the measuring time approaches the microsecond , the liquid droplet exhibits a large positive stiffness (it is small and negative in the long time limit). Although clearly controlled by surface effects , it compares to the stiffness of a solid nanobridge with a 1 GigaPa Young modulus. We argue that as evaporation and condensation gradually lose efficiency , the contact li...
Extended Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems
Figure 1: Overview of the grip pen sensing tool. Left.The hardware grip sensing tool is attached ... more Figure 1: Overview of the grip pen sensing tool. Left.The hardware grip sensing tool is attached to a regular pen. A sensitive matrix is wrapped around the body of the pen, and data processing algorithms are performed to detect grasp posture.
Proceedings of the 18th ACM International Conference on Interaction Design and Children
This PhD project is multidisciplinary, at the intersection of Early Childhood Education, Design, ... more This PhD project is multidisciplinary, at the intersection of Early Childhood Education, Design, and Human-Computer Interaction. The PhD goal aim at developing new approaches for early childhood education focusing on the role of body in the learning process. We leverage digital tangible and interactive technologies to develop specific scenarios that are evaluated in preschools. Our work proposes novel paradigms and uses of digital technologies currently not found in typical preschool environments.
The invention relates to an optical device for interferometric analysis of the surface of an obje... more The invention relates to an optical device for interferometric analysis of the surface of an object condition (2), comprising a light source (1); an optical fiber (42) adapted to receive the incident light wave to transmit it to the object (2); a detector (9) adapted to detect a combination of a light wave (45) reflected by the optical fiber and a light wave (46) reflected by the object; and wherein the optical fiber (42) has a free end shaped cone having an angle at the top between 15 and 25 degrees, the tip of the cone having dimensions of less than 50 x 50 nm, and the tip of the cone is disposed , in use, at a distance from the surface of the object between 5 and 50 .mu.m.
Five fold i-AlPdMn surface prepared under UHV by ion bombardment and annealing was so far conside... more Five fold i-AlPdMn surface prepared under UHV by ion bombardment and annealing was so far considered to be bulk terminated. This result was substantially based on a quantitative LEED analyses [1]. Analysis of the specular rod in a X ray diffraction experiment at grazing incidence supported this result [2]. We present a new study of this surface by high resolution X ray diffraction at normal incidence. In this Bragg configuration the diffraction peak 18 – 29 for instance is at a photon energy of 2.873keV, the 72 – 116 reflection at 5.725keV. This results in an analyzed thickness of the sample surface of a few micrometers.The surface was cleaned by ion bombardment. During annealing (T≅880K), we clearly observed the progressive disappearance of the initial Bragg peak characteristic of the as cast bulk sample. Conversely a new Bragg peak grows at an energy position shifted by 1eV compared to the position of the original Bragg peak. This is a clear signature for an irreversible structura...
In this article, we measure the viscous damping G″, and the associated stiffness G′, of a liquid ... more In this article, we measure the viscous damping G″, and the associated stiffness G′, of a liquid flow in sphere-plane geometry over a large frequency range. In this regime, the lubrication approximation is expected to dominate. We first measure the static force applied to the tip. This is made possible thanks to a force feedback method. Adding a sub-nanometer oscillation of the tip, we obtain the dynamic part of the interaction with solely the knowledge of the lever properties in the experimental context using a linear transformation of the amplitude and phase change. Using a Force Feedback Microscope (FFM), we are then able to measure simultaneously the static force, the stiffness, and the dissipative part of the interaction in a broad frequency range using a single AFM probe. Similar measurements have been performed by the Surface Force Apparatus (SFA) with a probe radius hundred times bigger. In this context, the FFM can be called nano-SFA.
In the past few years the heteroepitaxy on Si substrates of the semiconducting orthorhombic disil... more In the past few years the heteroepitaxy on Si substrates of the semiconducting orthorhombic disilicide β-FeSi2 has been extensively studied since it might be of potential applications in integrated optoelectronic devices, due to its optical gap measured closely to 0.85 eV. During the course of these investigations several unexpected pseudomorphic phases of ultra thin FeSi2 layers have been observed on top of the Si substrates. The growth of these phases and their physicochemical properties have been investigated with a large variety of preparation methods and surface techniques. A particular attention will be paid to the mechanisms of stabilization of such metastable phases due to their epitaxy on Si substrates, and to their transition, both electronic and structural, towards the β-FeSi2 phase. Recent findings concerning the growth at low temperature of the α-FeSi2 phase will also be discussed since it might shed light on the hierarchy of these phase transitions.
An overview of different strategies recently proposed to tune, by mechanical actuation or phase t... more An overview of different strategies recently proposed to tune, by mechanical actuation or phase transition, the near-field heat transfer between two media is presented. These results open the way to an efficient active management of heat transfer at nanoscale.
Atomic Force Microscopy (AFM) conventional static force curves and Force Feedback Microscopy (FFM... more Atomic Force Microscopy (AFM) conventional static force curves and Force Feedback Microscopy (FFM) force curves acquired with the same cantilever at the solid/air and solid/liquid interfaces are here compared. The capability of the FFM to avoid the jump to contact leads to the complete and direct measurement of the interaction force curve, including the attractive short-range van der Waals and chemical contributions. Attractive force gradients five times higher than the lever stiffness do not affect the stability of the FFM static feedback loop. The feedback loop keeps the total force acting on the AFM tip equal to zero, allowing the use of soft cantilevers as force transducers to increase the instrumental sensitivity. The attractive interactions due to the nucleation of a capillary bridge at the native oxide silicon/air interface or due to a DLVO interaction at the mica/deionized water interface have been measured. This set up, suitable for measuring directly and quantitatively interfacial forces, can be exported to a SFA (Surface Force Apparatus).
It has been predicted theoretically that for distances smaller than the peak wavelength of the bl... more It has been predicted theoretically that for distances smaller than the peak wavelength of the blackbody spectrum, radiative heat transfer can be increased by the contribution of evanescent waves [1]. These effects have already been observed but a quantitative comparison is still missing. We measure the heat flux between a sphere and a plate as a function of the sphere-plate distance. We find a good agreement between the experimental and theoretical results . Particularly, the distance dependence is well reproduced by the theory in a large range of gap widths: 50nm-2μm.
ABSTRACT Nanotechnology has been touted as the next ‘industrial revolution’ of our modern age. In... more ABSTRACT Nanotechnology has been touted as the next ‘industrial revolution’ of our modern age. In order for successful research, development, and social discourses to take place in this field, education research is needed to inform the development of standards, course development, and workforce preparation. In addition, there is a growing need to educate citizens and students about risks, benefits, and social and ethical issues related to nanotechnology. This position paper describes the advancements that have been made in nanoscale science and nanotechnology, and the challenges that exist to educate students and the public about critical nanoscience concepts. This paper reviews the current research on nanotechnology education including curricula, educational programs, informal education, and teacher education. Furthermore, the unique risks, benefits and ethics of these unusual technological applications are described in relation to nanoeducation goals. Finally, we outline needed future research in the areas of nanoscience content, standards and curricula, nanoscience pedagogy, teacher education, and the risks, benefits, and social and ethical dimensions for education in this emerging field.
Les poussières sont partout. Chacune est imperceptible mais elles sont néanmoins toujours présent... more Les poussières sont partout. Chacune est imperceptible mais elles sont néanmoins toujours présentes et s'imposent dans nos vies. Leur apparition dans un appartement est la marque de l'absence prolongée ou « d'une certaine négligence ménagère ». La poussière est synonyme de corvées, de temps qui passe, et toujours de nuisances en particulier pour nos bronches, nos yeux… Pour Galilée, la Lune est terreuse. A cet égard peut être même un peu trop. Taper « poussière lune apollo » dans Google montre à quel point cette fine poussière lunaire peut être une plaie. Les tourbillons de poussières géants vus sur Mars, les « Dust Devil », montrent aussi combien les poussières sont vraiment partout 1 .
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