Project number:

PROJECT TITLE

Dynamics of polymers and surfactants near interfaces

PROJECT SUPERVISOR

Name: Josep BONET AVALOS

e-mail:
josep.bonet@urv.net
Telephone: + 34 977 55 96 45



DESCRIPTION

 


Overview:

In this project we will address the problem of constructing mesoscopic models suitable for the study of the static and dynamic behaviour of polymer, surfactant molecules as well as their molecular aggregates. In particular, attention will be paid to the kinetics of micelle formation and the dynamics of the different structural changes under the variation of the control parameters governing the behaviour of polymers and surfactants near interfaces.

Background and State of the Art:

The capability of surfactants and copolymers to form microphases controlled by external conditions, such as bulk concentrations, temperature, pH, etc. can be used in the field of nanotechnology with different purposes, ranging from tailor-made materials, pharmacological applications or even for tissue remediation.

It is of great interest to determine the variables and paths that control the desired behaviour at such microscopic scale. However, it is well known that a system involving polymers, nanostructures as well as small particles like solvent molecules will involve many separate time and length scales, making the analysis from the point of view of computer simulations very difficult. Mesoscopic models are thus required to describe the dynamics at the appropriate length scale.

Mesoscopic models are descriptions of the system that lie between the purely molecular point of view and a macroscopic description based on fields like temperature, composition or momentum. Mesoscopic models combine important fluctuations, dissipative processes in a combination of microscopic interaction potentials and macroscopic thermodynamic potentials. The ultimate goal of the proposed research is to devise a consistent way to bridge the valley between a microscopic and a macroscopic description aiming at building an effective and predictive tool to describe the interesting phenomenology at the nanoscale.

Project Contribution and Methodology:

At present, research based on molecular simulations in the area of Soft Condensed Matter is being carried out in the group of Interfaces and Polymers and Complex Systems. The most relevant topics involve i) equilibrium properties of polymers at interfaces ii) structural transition in surfactant aggregates and iii) Dissipative Particle Dynamics methods. The present project is mainly concerned with the latter.

In the group we have experience in stochastic processes as well as in methodologies based on Brownian motion. Furthermore, we have also developed tools to study the complex equilibrium behaviour of polymers and surfactant at interfaces and in the bulk.

The methodology to be employed is the use of the existing Dissipative Particle Dynamics codes, and to develop new algorithms for the interesting situations that we have described above. This will require familiarisation with the codes, code development as well as mesoscopic model development.

The ideal candidate:

It is essential for the success of the candidate to show aptitude for the abstract reasoning, since the most of the work will involve computer implementation of the developed algorithms as well as analysis of results. Thus, graduates of Engineering and Physics have the appropriate background, although Chemistry graduates can also do well if they do not fear formal work.

Finishing this project:

At the end of the PhD the student will have acquired expertise in modelling. Such a formation will be suitable to start independent work in many Chemical Engineering departments at universities. In addition, the applied side of the research will make the student an excellent candidate to be incorporated in many research and development groups of industries related to cosmetics, pharmacology and polymer based industries.

References:

[1] J. Bonet Avalos, A.D. Mackie, Dissipative Particle Dynamics with Energy Conservation, Europhysics Letters, 40 (1997), 141
[2]
P. Wojtaszczyk and J. Bonet Avalos, Influence of Hydrodynamic Interactions on the Kinetics of the Colloidal Particles Adsorption, Physical Review Letters, 80 (1998), 754
[3]
A.D. Mackie, J. Bonet Avalos, and V. Navas, Dissipative Particle Dynamics with Energy Conservation: Modelling of Heat Flow, Physical Chemistry Chemical Physics, 1 (1999), 2039
[4] J. Bonet Avalos and A.D. Mackie, Dynamic and Transport Properties of Dissipative Particle Dynamics with Energy Conservation, Journal of Chemical Physics, 111 (1999), 5267
[5] I. Pagonabarraga and D. Frenkel. Dissipative particle dynamics for interacting systems. J. Chem. Phys., 115 (2001), 5015


(c) 2003, Doctoral Studies in Chemical and Process Engineering, Universitat Rovira i Virgili