Axe : Intégration micro- et nanofluidiques - pnipam

  • Stimuli responsive polymers: principle
    • Temperature: pNIPAM, PEG, PDEAM, PMEAM
    • Light: copolymers of azobenzene and PDMA or PNIPAM
    • pH: copolymers of 2-hydroxyethyl methacrylate and acrylic acide
    • Potential: charged copolymers
  • pNIPAM (poly(N-isopropyl acrylamide))

Thermo-responsive polymer: PNIPAM



Reversible switch around 32°C (LCST, Lower Critical Solution Temperature)
from a hydrophilic swollen state to a hydrophobic collapsed state

  • Grafting technology
2 Steps grafting technology
  • Organosilane intermediate layer
  • in situ polymerisation (grafting from) of pNIPAM
2 types of chemistry
  • Silane: Tri-(methoxysilyl) propyl methacrylate (TMSPM)
    • Grafting: TEMED/Amonium Persulfate
    • Density: 1010 chains / cm2
  • Silane: Tri-(Mercaptopropyl) trimethoxysilane (MPTMS)
    • Grafting: Dioxane
    • Density: 1011-13 chains / cm2
  • EHD valves
Variation of EOF mobility in
pNIPAM end-grafted channels
versus temperatureVotre texte


  • Fully reversible purification module operating in aqueous solution
The idea is to use the Hydrophilic/hydrophobic transition of switchable thermo responsive polymers to realize reversible purification or pre-concentration nanocolumns. Proteins & peptides adsorb on the heated surface while they are released as the surface cools down.

Nano-LC columns are fabricated from a pyrex substrate with 90 nm thick Ti/Au thermal heater and a PDMS cover lid with 2 level fluidic channels. Functionalized beads are trapped and packed in the main channel due to the height restriction and act as a µcolumn

Adsorption of albumin-fluorescein on 5µm beads (phosphate buffer)


Publications :

Nanoscale actuation of electrokinetic flow on thermoreversible surfaces G. Paumier, J. Sudor ,A.-M. Gue, F. Vinet, M. Li, Y. J. Chabal, A. Estève, M. Djafari-Rouhani Electrophoresis, 29, (2008) 1245-1252

A New insight into the understanding of the collapsed form of Poly(N-isopropylacrylamide molecules A. Estève, A. Bail, G. Landa, A. Dkhissi, M. Djafari Rouhani, J. Sudor, A.M. Gué J. of Chemical Physics, 340 (1), p.12-16, Nov 2007