اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدAdvection kinetics induced self assembly of colloidal nanoflakes into microscale floral structures
79
0
0.0
(
0
)
تأليف
Purbarun Dhar
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
This article explores the governing role of the internal hydrodynamics and advective transport within sessile colloidal droplets on the self assembly of nanostructures to form floral patterns. Water acetone binary fluid and Bi2O3 nanoflakes based complex fluids are experimented with. Microliter sessile droplets are allowed to vaporize and the dry out patterns are examined using scanning electron microscopy. The presence of distributed self assembled rose like structures is observed. The population density, structure and shape of the floral structures are noted to be dependent on the binary fluid composition and nanomaterial concentration. Detailed microscopic particle image velocimetry analysis is undertaken to qualitatively and quantitatively describe the solutal Marangoni advection within the evaporating droplets. It has been shown that the kinetics, regime and location of the internal advection are responsible factors towards the hydrodynamics influenced clustering, aggregation and self-assembly of the nanoflakes. In addition, the size of the nanostructures and the complex fluids.
قيم البحث
اقرأ أيضاً
We study by simulation the physics of two colloidal particles in a cholesteric liquid crystal with tangential order parameter alignment at the particle surface. The effective force between the pair is attractive at short range and favors assembly of
colloid dimers at specific orientations relative to the local director field. When pulled through the fluid by a constant force along the helical axis, we find that such a dimer rotates, either continuously or stepwise with phase-slip events. These cases are separated by a sharp dynamical transition and lead, respectively, to a constant or an ever-increasing phase lag between the dimer orientation and the local nematic director.
We outline a basic strategy of how self-propulsion can be used to improve the yield of a typical colloidal self-assembly process. The success of this approach is predicated on the thoughtful design of the colloidal building block as well as how self-
propulsion is endowed to the particle. As long as a set of criteria are satisfied, it is possible to significantly increase the rate of self-assembly, and greatly expand the window in parameter space where self-assembly can occur. In addition, we show that by tuning the relative on/off time of the self-propelling force it is possible to modulate the effective speed of the colloids allowing for further optimization of the self-assembly process.
Colloidal crystals exhibit structural color without any color pigment due to the crystals periodic nanostructure, which can interfere with visible light. This crystal structure is iridescent as the resulting color changes with the viewing or illumina
tion angle, which limits its use for printing or displays. To eliminate the iridescent property, it is important to make the packing of the colloidal nanoparticles disordered. Here, we introduce a drop-casting method where a droplet of a water- ethanol mixture containing monodisperse polymer-coated silica nanoparticles creates a relatively uniform and non-iridescent deposit after the droplet evaporates completely on a heated substrate. The uniformity is caused by a thermal Marangoni flow and fast evaporation effects due to the heated substrate, whereas non-iridescence is the outcome of short-range-ordered packing of nanoparticles by depletion attraction and friction effects produced by polymer brushes. We show that the colors of the final deposits from individual droplets remain unchanged while the viewing angle is varied under ambient light. We expect that the coating method is compatible with ink-jet printing and the uniformly coated self-assembled non-iridescent nanostructures have potential for color displays using reflection mode and other optical devices.
In this review we discuss recent advances in the self-assembly of self-propelled colloidal particles and highlight some of the most exciting results in this field with a specific focus on dry active matter. We explore this phenomenology through the l
ens of the complexity of the colloidal building blocks. We begin by considering the behavior of isotropic spherical particles. We then discuss the case of amphiphilic and dipolar Janus particles. Finally, we show how the geometry of the colloids and/or the directionality of their interactions can be used to control the physical properties of the assembled active aggregates, and suggest possible strategies on how to exploit activity as a tunable driving force for self-assembly. The unique properties of active colloids lend promise for the design of the next generation of functional, environment-sensing microstructures able to perform specific tasks in an autonomous and targeted manner.
From dumbbells to FCC crystals, we study the self-assembly pathway of amphiphatic, spherical colloidal particles as a function of the size of the hydrophobic region using molecular dynamics simulations. Specifically, we analyze how local inter-partic
le interactions correlate to the final self-assembled aggregate and how they affect the dynamical pathway of structure formation. We present a detailed diagram separating the many phases that we find for different sizes of the hydrophobic area, and uncover a narrow region where particles self-assemble into hollow, faceted cages that could potentially find interesting engineering applications.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
