Rodrigo Ledesma-Aguilar

OCCAM

06/2013 Check how wetting and surface friction affect the stability of moving fronts
09/2013 Check how microorganisms can exploit elastic surfaces to swim more efficiently
Rodrigo Ledesma-Aguilar
Post Doctoral Research Assistant

Oxford Centre for Collaborative Applied Mathematics
24-29 St. Giles', Oxford OX1 3LB
United Kingdom

Email: ledesma at maths.ox.ac.uk
Phone: +44 (0) 1865 615172

About me

I am a postdoctoral fellow working in Dr. Dominic Vella's group at the Oxford Centre for Collaborative Applied Mathematics and a Fulford Junior Research Fellow at Somerville College. Before that, I worked as a Marie Curie Intra European Fellow in Prof. Julia Yeomans group at the University of Oxford.

My research covers topics in elastocapillarity, active matter and wetting phenomena. Recently, I worked in numerical simulations of the dynamics of microscopic swimmers at low Reynolds numbers and the driven translocation of polymer chains through nanopores.

I am also interested in the dynamics of fluids in microfluidic environments, particularly in capillary flows on hydrophilic and hydrophobic surfaces.

I graduated as a Doctor in Physics from the University of Barcelona in 2009, where I worked with Prof. Aurora Hernández-Machado and Prof. Ignacio Pagonabarraga. Before that, I obtained my Diploma in Chemical Engineering in 2004 from the National Autonomous University of Mexico, where I worked under the supervision of Prof. Eugenia Corvera Poiré.

You can check my CV here.

Preprints

  • with Siti Aminah Setu, Roel Dullens, Aurora Hernández-Machado, Ignacio Pagonabarraga and Dirk Aarts
    Contact line dynamics in superconfined fluids

  • with Dominic Vella and Julia Yeomans
    Lattice-Boltzmann simulations of drop evaporation

  • with Damien P. Foster and Julia Yeomans
    Translocation of neutral polymers against flow

Publications

Teaching

1st year Physics: mechanics, special relativity, optics, vectors and matrices, vector calculus and multiple integrals, normal modes and wave motion. 2nd year Physics: statistical mechanics and kinetic theory of gases, electromagnetism.

Press

My research with Prof. Hernández-Machado and Prof. Pagonabarraga on microscale drop production was featured by the University of Barcelona press office. You can see the note here.

Microswimmers and their environment

Based on theoretical and numerical modeling, we are currently studying the interplay between microswimmers and their environment. We are interested in understanding how single and collective interactions between swimmers are affected by structured surfaces and interfaces, external biasing and local fluid properties. We hence aim at applications that exploit active systems, by controlling existing biological environments, such as bacterial baths and biofilms, and by developing new tailored technologies, such as swimmer-actuated microfluidic devices.

















Polymer translocation through narrow pores

The passage of polymer chains through narrow pores is an ubiquitous process in nature. Biopolymers, such as DNA and RNA, have to cross a multitude of barriers to perform different biological functions, for example, in translocating through cellular membrane pores or when ejecting from viral capsids. Understanding the way in which polymer chains translocate through nanometric pores is very important, as it may open the possibility of new and powerful technologies, as for example, the potential sequencing of DNA molecules or the sorting of polymer chains according to their instrinsic properties (chain or monomer size, etc.) using smart entropic traps.

We are currently studying the way in which single polymer chains get into a nanopore when forced by an underlying fluid flow. We focus on situations where the translocation of the chain is affected by its length and by the geometry of the constriction.



Partially confined polymer chain in a narrow pore











Making drops using wetting properties

The controlled formation of microdrops is a very important process in microfluidics. We have found that it is possible to exploit the wettability of a solid substrate when forcing a liquid microfilament on it to trigger a new kind of instability. The instability is related to how fast the contact line of the filament moves relative to the motion of the filament as a whole, and it involves the balance of capillary forces versus viscous and driving forces. It turns out that this balance is impossible to sustain above a critical velocity that depends on the wetting properties of the solid, and leads to the controlled formation of microsized drops. By tuning the wettability of the substrate and the driving velocity of the filament, it is possible to control the size and the rate emission of the droplets.

Controlled drop emission by wetting properties

Last updated: September 05, 2013