ترغب بنشر مسار تعليمي؟ اضغط هنا

Enhanced motility in a binary mixture of active nano/microswimmers

114   0   0.0 ( 0 )
 نشر من قبل Pulak Kumar Ghosh Dr.
 تاريخ النشر 2020
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

It is often desirable to enhance the motility of active nano- or microscale swimmers such as, e.g., self-propelled Janus particles as agents of chemical reactions or weak sperm cells for better chances of successful fertilization. Here we tackle this problem based on the idea that motility can be transferred from a more active guest species to a less active host species. We performed numerical simulations of motility transfer in two typical cases, namely for interacting particles with weak inertia effect, by analyzing their velocity distributions, and for interacting overdamped particles, by studying their effusion rate. In both cases we detected motility transfer with a motility enhancement of the host species of up to a factor of four. This technique of motility enhancement can find applications in chemistry, biology and medicine.



قيم البحث

اقرأ أيضاً

We study effective two- and three-body interactions between non-active colloidal inclusions in an active bath of chiral or non-chiral particles, using Brownian Dynamics simulations within a standard, two-dimensional model of disk-shaped inclusions an d active particles. In a non-chiral active bath, we first corroborate previous findings on effective two-body repulsion mediated between the inclusions by elucidating the detailed non-monotonic features of the two-body force profiles, including a primary maximum, and a secondary hump at larger separations that was not previously reported. We then show that these features arise directly from the formation, and sequential overlaps, of circular layers (or rings) of active particles around the inclusions, as the latter are brought to small surface separations. These rings extend to radial distances of a few active-particle radii from the surface of inclusions, giving the hard-core inclusions relatively thick, soft, repulsive shoulders, whose multiple overlaps then enable significant (non-pairwise) three-body forces in both non-chiral and chiral active baths. The resulting three-body forces can even exceed the two-body forces in magnitude and display distinct repulsive and attractive regimes at intermediate to large self-propulsion strengths. In a chiral active bath, we show that, while active particles still tend to accumulate at the immediate vicinity of the inclusions, they exhibit strong depletion from the intervening region between the inclusions, and partial depletion from relatively thick, circular, zones further away from the inclusions. In this case, the effective, predominantly repulsive, interactions between the inclusions turn to active, chirality-induced, depletion-type attractions, acting over an extended range of separations.
We study diffusion of heat in an aqueous suspension of disc shaped nanoparticles of Laponite, which has finite elasticity and paste-like consistency, by using the Mach-Zehnder interferometer. We estimate the thermal diffusivity of the suspension by c omparing the experimentally obtained temperature distribution to that with analytical solution. We observe that despite highly constrained Brownian diffusivity of particles owing to its soft glassy nature, suspensions at very small concentrations of Laponite demonstrates significant enhancement in thermal diffusivity. We correlate the observed enhancement with the possible microstructures of the Laponite suspension.
A gold-capped Janus particle suspended in a near-critical binary liquid mixture can self-propel under illumination. We have immobilized such a particle in a narrow channel and studied the nonequilibrium dynamics of a binary solvent around it, using e xperiment and numerical simulations. For the latter we consider both a purely diffusive and a hydrodynamic model. All approaches indicate that the early time dynamics is purely diffusive and characterized by composition layers traveling with a constant speed from the surface of the colloid into the bulk. Subsequently, hydrodynamic effects set in and the transient state is destroyed by strong nonequilibrium concentration fluctuations, which arise as a result of the temperature gradient and the vicinity of the critical point of the binary liquid mixture. They give rise to a complex, permanently changing coarsening patterns. For a mobile particle, the transient dynamics results in propulsion in the direction opposite to that observed after the steady state is attained.
We study the fate of an impurity in an ultracold heteronuclear Bose mixture, focusing on the experimentally relevant case of a $^{41}$K-$^{87}$Rb mixture, with the impurity in a $^{41}$K hyperfine state. Our work provides a comprehensive description of an impurity in a BEC mixture with contact interactions across its phase diagram. We present results for the miscible and immiscible regimes, as well as for the impurity in a self-bound quantum droplet. Here, varying the interactions, we find novel, exotic states where the impurity localizes either at the center or at the surface of the droplet.
Active systems contain self-propelled particles and can spontaneously self-organize into patterns making them attractive candidates for the self-assembly of smart soft materials. One key limitation of our present understanding of these materials hing es on the complexity of the microscopic mechanisms driving its components forward. Here, by combining experiments, analytical theory and simulations we explore such a mechanism for a class of active system, modular microswimmers, which self-assemble from colloids and ion-exchange resins on charged substrates. Our results unveil the self-assembly processes and the working mechanism of the ion-exchange driven motors underlying modular microswimmers, which have so far been illusive, even qualitatively. We apply these motors to show that modular microswimmers can circumvent corners in complex environments and move uphill. Our work closes a central knowledge gap in modular microswimmers and provides a facile route to extract mechanical energy from ion-exchange processes.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا