Partenaires

Logo CNRS Logo UPMC


 
 
 

Rechercher

Sur ce site

Sur le Web du CNRS

 
 
 



Accueil du site > Offres d’emploi > Stages > [Master 2] Adsorption of polyelectrolytes chains in charged nanochannels

[Master 2] Adsorption of polyelectrolytes chains in charged nanochannels

par Nicolas Jouault - 14 novembre

Internship period : end of January to beginning of July

Encadrement : Nicolas Jouault (équipe MEM)

Description of the project

Polyelectrolytes (PEs) are polymers carrying electric charges due to the dissociation in polar solvents of ionic groups present on the chain. Compared to neutral polymers, the existence of theses charges has direct consequences of the PEs behavior in solution[1,2]. In particular, the PE adsorption on concave surfaces has been less studied[3] while it is typically encountered in nanoporous materials and have interesting potential applications such as ionic separation[4], catalysis[5] or ionic rectification for single molecules analysis[6].

In this internship, we propose to study the penetration and adsorption of PE inside nanoporous anodic aluminum oxide (AAO) membrane. AAOs are composed of parallel and non-connected nanochannels with variable characteristic sizes (diameter from 10 to 200 nm and length up to 500 μm)[7]. A typical scanning electron microscopy image of the AAO top surface is shown in Fig. 1. We’ll follow the kinetic of penetration and the adsorption of PE in AAOs by combining different techniques such as infrared spectroscopy, liquid flow measurements and streaming potential measurements. The latter provides information about the surface charge of the AAO, more precisely the ζ-potential. At neutral pH (like in pure water) the AAO is positively charged. If a negative PE is entering and adsorbs at the surface, the surface charge will become negative. Then, the evolution of the ζ-potential with time will allow us to monitor the kinetic of penetration and adsorption in AAO. Coupled with flow measurement, we can also have access to the thickness of the adsorbed layer. A parametric study will be performed to investigate the influence of nanochannel diameter, surface charge and nature of PE (weak or strong PE) on the PE behavior in charged nanochannels.

Specific techniques or methods

Synthesis of nanoporous alumina by anodization, scanning electron microscopy, streaming potential measurements (in collaboration with Didier Lairez from LSI at École Polytechnique), Infrared spectroscopy and flow measurements

References

[1] M. Muthukumar, Macromolecules 50, 9528 (2017).
[2] A. V. Dobrynin and M. Rubinstein, Progress in Polymer Science 30, 1049 (2005).
[3] A. Christoulaki, A. Chennevière, E. Dubois, and N. Jouault, Nanoscale 11, 2148 (2019).
[4] J. A. Armstrong, E. E. L. n. Bernal, A. Yaroshchuk, and M. L. Bruening, Langmuir 29, 10287 (2013).
[5] D. M. Dotzauer, J. Dai, L. Sun, and M. L. Bruening, Nano Letters 6, 2268 (2006).
[6] M. Ali, B. Yameen, J. Cervera, P. Ramírez, R. Neumann, W. Ensinger, W. Knoll, and O. Azzaroni, J. Am. Chem. Soc 132, 8338 (2010).
[7] A. Christoulaki, A. Chenneviere, I. Grillo, L. Porcar, E. Dubois, and N. Jouault, Journal of Applied Crystallography 52, 745 (2019).