The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Jeremie Palacci - One of the best experts on this subject based on the ideXlab platform.
-
diffusiophoretic design of self spinning Microgears from colloidal microswimmers
Soft Matter, 2018Co-Authors: Antoine Aubret, Jeremie PalacciAbstract:The development of strategies to assemble microscopic machines from dissipative building blocks are essential on the route to novel active materials. We recently demonstrated the hierarchical self-assembly of phoretic microswimmers into self-spinning Microgears and their synchronization by diffusiophoretic interactions [Aubret et al., Nat. Phys., 2018]. In this paper, we adopt a pedagogical approach and expose our strategy to control self-assembly and build machines using phoretic phenomena. We notably introduce Highly Inclined Laminated Optical sheets microscopy (HILO) to image and characterize anisotropic and dynamic diffusiophoretic interactions, which cannot be performed by conventional fluorescence microscopy. The dynamics of a (haematite) photocatalytic material immersed in (hydrogen peroxide) fuel under various illumination patterns is first described and quantitatively rationalized by a model of diffusiophoresis, the migration of a colloidal particle in a concentration gradient. It is further exploited to design phototactic microswimmers that direct towards the high intensity of light, as a result of the reorientation of the haematite in a light gradient. We finally show the assembly of self-spinning Microgears from colloidal microswimmers and carefully characterize the interactions using HILO techniques. The results are compared with analytical and numerical predictions and agree quantitatively, stressing the important role played by concentration gradients induced by chemical activity to control and design interactions. Because the approach described hereby is generic, this works paves the way for the rational design of machines by controlling phoretic phenomena.
-
targeted assembly and synchronization of self spinning Microgears
arXiv: Soft Condensed Matter, 2018Co-Authors: Antoine Aubret, Mena Youssef, Stefano Sacanna, Jeremie PalacciAbstract:Self-assembly is the autonomous organization of components into patterns or structures: an essential ingredient of biology and a desired route to complex organization. At equilibrium, the structure is encoded through specific interactions, at an unfavorable entropic cost for the system. An alternative approach, widely used by Nature, uses energy input to bypass the entropy bottleneck and develop features otherwise impossible at equilibrium. Dissipative building blocks that inject energy locally were made available by recent advance in colloidal science but have not been used to control self-assembly. Here we show the robust formation of self-powered rotors and dynamical superstructures from active particles and harness non-equilibrium phoretic phenomena to tailor interactions and direct self-assembly. We use a photoactive component that consumes fuel, hematite, to devise phototactic microswimmers that form self-spinning Microgears following spatiotemporal light patterns. The gears are coupled via their chemical clouds and constitute the elementary bricks of synchronized superstructures, which autonomously regulate their dynamics. The results are quantitatively rationalized on the basis of a stochastic description of diffusio-phoretic oscillators dynamically coupled by chemical gradients to form directional interactions. Our findings demonstrate that non-equilibrium phenomena can be harnessed to shape interactions and program hierarchical constructions. It lays the groundwork for the self-assembly of dynamical architectures and synchronized micro-machinery.
-
targeted assembly and synchronization of self spinning Microgears
Nature Physics, 2018Co-Authors: Antoine Aubret, Mena Youssef, Stefano Sacanna, Jeremie PalacciAbstract:Self-assembly is the autonomous organization of components into patterns or structures: an essential ingredient of biology and a desired route to complex organization1. At equilibrium, the structure is encoded through specific interactions2–8, at an unfavourable entropic cost for the system. An alternative approach, widely used by nature, uses energy input to bypass the entropy bottleneck and develop features otherwise impossible at equilibrium9. Dissipative building blocks that inject energy locally were made available by recent advances in colloidal science10,11 but have not been used to control self-assembly. Here we show the targeted formation of self-powered Microgears from active particles and their autonomous synchronization into dynamical superstructures. We use a photoactive component that consumes fuel, haematite, to devise phototactic microswimmers that form self-spinning Microgears following spatiotemporal light patterns. The gears are coupled via their chemical clouds by diffusiophoresis12 and constitute the elementary bricks of synchronized superstructures, which autonomously regulate their dynamics. The results are quantitatively rationalized on the basis of a stochastic description of diffusio-phoretic oscillators dynamically coupled by chemical gradients. Our findings harness non-equilibrium phoretic phenomena to program interactions and direct self-assembly with fidelity and specificity. It lays the groundwork for the autonomous construction of dynamical architectures and functional micro-machinery. Active colloidal particles are shown to be capable of aggregating into stable spinning clusters that constitute self-powered Microgears. The demonstration reveals a new design principle for micromachinery using dissipative building blocks.
Antoine Aubret - One of the best experts on this subject based on the ideXlab platform.
-
diffusiophoretic design of self spinning Microgears from colloidal microswimmers
Soft Matter, 2018Co-Authors: Antoine Aubret, Jeremie PalacciAbstract:The development of strategies to assemble microscopic machines from dissipative building blocks are essential on the route to novel active materials. We recently demonstrated the hierarchical self-assembly of phoretic microswimmers into self-spinning Microgears and their synchronization by diffusiophoretic interactions [Aubret et al., Nat. Phys., 2018]. In this paper, we adopt a pedagogical approach and expose our strategy to control self-assembly and build machines using phoretic phenomena. We notably introduce Highly Inclined Laminated Optical sheets microscopy (HILO) to image and characterize anisotropic and dynamic diffusiophoretic interactions, which cannot be performed by conventional fluorescence microscopy. The dynamics of a (haematite) photocatalytic material immersed in (hydrogen peroxide) fuel under various illumination patterns is first described and quantitatively rationalized by a model of diffusiophoresis, the migration of a colloidal particle in a concentration gradient. It is further exploited to design phototactic microswimmers that direct towards the high intensity of light, as a result of the reorientation of the haematite in a light gradient. We finally show the assembly of self-spinning Microgears from colloidal microswimmers and carefully characterize the interactions using HILO techniques. The results are compared with analytical and numerical predictions and agree quantitatively, stressing the important role played by concentration gradients induced by chemical activity to control and design interactions. Because the approach described hereby is generic, this works paves the way for the rational design of machines by controlling phoretic phenomena.
-
targeted assembly and synchronization of self spinning Microgears
arXiv: Soft Condensed Matter, 2018Co-Authors: Antoine Aubret, Mena Youssef, Stefano Sacanna, Jeremie PalacciAbstract:Self-assembly is the autonomous organization of components into patterns or structures: an essential ingredient of biology and a desired route to complex organization. At equilibrium, the structure is encoded through specific interactions, at an unfavorable entropic cost for the system. An alternative approach, widely used by Nature, uses energy input to bypass the entropy bottleneck and develop features otherwise impossible at equilibrium. Dissipative building blocks that inject energy locally were made available by recent advance in colloidal science but have not been used to control self-assembly. Here we show the robust formation of self-powered rotors and dynamical superstructures from active particles and harness non-equilibrium phoretic phenomena to tailor interactions and direct self-assembly. We use a photoactive component that consumes fuel, hematite, to devise phototactic microswimmers that form self-spinning Microgears following spatiotemporal light patterns. The gears are coupled via their chemical clouds and constitute the elementary bricks of synchronized superstructures, which autonomously regulate their dynamics. The results are quantitatively rationalized on the basis of a stochastic description of diffusio-phoretic oscillators dynamically coupled by chemical gradients to form directional interactions. Our findings demonstrate that non-equilibrium phenomena can be harnessed to shape interactions and program hierarchical constructions. It lays the groundwork for the self-assembly of dynamical architectures and synchronized micro-machinery.
-
targeted assembly and synchronization of self spinning Microgears
Nature Physics, 2018Co-Authors: Antoine Aubret, Mena Youssef, Stefano Sacanna, Jeremie PalacciAbstract:Self-assembly is the autonomous organization of components into patterns or structures: an essential ingredient of biology and a desired route to complex organization1. At equilibrium, the structure is encoded through specific interactions2–8, at an unfavourable entropic cost for the system. An alternative approach, widely used by nature, uses energy input to bypass the entropy bottleneck and develop features otherwise impossible at equilibrium9. Dissipative building blocks that inject energy locally were made available by recent advances in colloidal science10,11 but have not been used to control self-assembly. Here we show the targeted formation of self-powered Microgears from active particles and their autonomous synchronization into dynamical superstructures. We use a photoactive component that consumes fuel, haematite, to devise phototactic microswimmers that form self-spinning Microgears following spatiotemporal light patterns. The gears are coupled via their chemical clouds by diffusiophoresis12 and constitute the elementary bricks of synchronized superstructures, which autonomously regulate their dynamics. The results are quantitatively rationalized on the basis of a stochastic description of diffusio-phoretic oscillators dynamically coupled by chemical gradients. Our findings harness non-equilibrium phoretic phenomena to program interactions and direct self-assembly with fidelity and specificity. It lays the groundwork for the autonomous construction of dynamical architectures and functional micro-machinery. Active colloidal particles are shown to be capable of aggregating into stable spinning clusters that constitute self-powered Microgears. The demonstration reveals a new design principle for micromachinery using dissipative building blocks.
C Sun - One of the best experts on this subject based on the ideXlab platform.
-
Micro-stereolithography of polymeric and ceramic microstructures
Sensors and Actuators A: Physical, 1999Co-Authors: Xueyi Zhang, X. N. Jiang, C SunAbstract:Micro-stereolithography (μSL) is a novel micro-manufacturing process which builds the truly 3D microstructures by solidifying the liquid monomer in a layer by layer fashion. In this work, an advanced μSL apparatus is designed and developed which includes an Ar+laser, the beam delivery system, computer-controlled precision x-y-z stages and CAD design tool, and in situ process monitoring systems. The 1.2 μm resolution of μSL fabrication has been achieved with this apparatus. The microtubes with high aspect ratio of 16 and real 3D microchannels and microcones are fabricated on silicon substrate. For the first time, μSL of ceramic Microgears has been successfully demonstrated.
-
www.elsevier.nlrlocatersna Micro-stereolithography of polymeric and ceramic microstructures
1998Co-Authors: Xueyi Zhang, X. N. Jiang, C SunAbstract:.Micro-stereolithography mSL is a novel micro-manufacturing process which builds the truly 3D microstructures by solidifying the liquid monomer in a layer by layer fashion. In this work, an advanced mSL apparatus is designed and developed which includes an Arq laser, the beam delivery system, computer-controlled precision x–y–z stages and CAD design tool, and in situ process monitoring systems. The 1.2 mm resolution of mSL fabrication has been achieved with this apparatus. The microtubes with high aspect ratio of 16 and real 3D microchannels and microcones are fabricated on silicon substrate. For the first time, mSL of ceramic Microgears has bee
Pierre Benech - One of the best experts on this subject based on the ideXlab platform.
-
modelization of the whispering gallery mode in microgear resonators using the floquet bloch formalism
IEEE Journal of Quantum Electronics, 2005Co-Authors: Kien Phan Huy, Alain Morand, Pierre BenechAbstract:In this paper, a two-dimensional (2-D) method describing the whispering gallery mode in a microgear resonator is presented. The microgear is a microdisk surrounded by a circular grating. The method, which is based on the Floquet-Bloch formalism, analytically describes the field within the disk and outside the grating. On the other hand, the field within the grating is calculated using a finite-difference scheme in polar coordinates. Matching the boundary conditions, it is possible to work in a forced oscillation regime or in a free oscillation regime (laser mode). The resonant wavelength and quality factor can then be deduced. Compared to the coupled mode theory and to 2-D finite-difference time-domain computations, the method is faster and more accurate. Moreover, a polarization effect of the microgear is demonstrated. The TE polarization experiences a Q-factor improvement contrary to TM polarization. Finally, microgear structures prove to be more efficient than micro flowers.
Zhou Jian - One of the best experts on this subject based on the ideXlab platform.
-
research on forming processes of Microgears with floating micro die
Materials Science and Technology, 2011Co-Authors: Zhou JianAbstract:Because the effect of friction on microforming increased quickly with the increasing of the ratio of surface to volume,in this paper,for the forming of microgear,a floating micro-die was designed,and isothermal forming tests of the Microgears were carried out.The results show that the friction can be used to improve the billet to flow into die cavity by the floating micro-die so that the forming load is decreased obviously,and the formed Microgears have good surface quality and microstructure.