Monthly Archive for: ‘July, 2011’

Phrase d’accroche

If you want to join our group, please contact us for information about graduate or undergraduate opportunities.

A few words about us

A few words about us

Our laboratory is located in a building devoted to nanosciences, the pavilion J. A, Bombardier situated on the highest point of the campus, next to Mont Royal. Our group is affiliated to the department of Chemistry in the Faculty of Arts and Sciences of the University of Montreal. It is also a Satellite laboratory of the Institute of Materials Nanoarchitectonics (MANA) of the National Institute of Material Science (NIMS) in Tsukuba (Japan).

What We do

Our research combines studies in fundamental physical chemistry, polymer science, surface chemistry, to applied fields such as nanomedicine and nanotoxicity. This interdisciplinary work involves synthesis and characterization of stimuli-responsive polymers as well as the design of gold nanoparticles and functionalized quantum dots for biomedical applications. To learn more about what we do, please visit our Research page.

Preferential adsorption and co-solvency of thermosensitive polymers in mixed solvents of water/methanol

F. Tanaka, T. Koga, H. Kojima, N. Xue, Winnik F. M. Preferential adsorption and co-solvency of thermosensitive polymers in mixed solvents of water/methanol, Macromolecules, 2011, 44, 2978-2989.

If two good solvents become poor for a polymer when mixed, the solvent pair is called a co-nonsolvent pair for the polymer. The sharp depression of the LCST by the co-nonsolvency in solutions of poly(N-isopropylacrylamide) in the mixed solvent of water and methanol is shown to be caused by the competitive hydrogen bonding of water and methanol molecules onto the polymer chains. On the basis of a new statistical-mechanical model for competitive hydrogen bonds, the degree of hydration θ(w) and of methanol binding θ(m), excess degree ΔθE of solvent binding, preferential adsorption coefficients Γ, LCST spinodal lines, and cloud-point depression ΔTcl are theoretically calculated and compared with the experimental results. The optimal composition xm(M) of methanol at which LCST takes the minimum value is studied as a function of the polymer molecular weight M. In the high molecular weight limit, it takes xm ≈ 0.35. The solution recovers a uniform state in the region of higher methanol composition. Such a peculiar phase separation is caused by the dehydration of the polymer chains by the mixed methanol molecules in a cooperative way.

Solvent induced amplification of the photoresponsive properties of α,ω-di-[4-cyanophenyl-4′-(6-hexyloxy)-azobenzene]-poly(N-isopropylacrylamide) in aqueous media

N. Ishii, J.I. Mamiya, T. Ikeda, F. M. Winnik, Solvent induced amplification of the photoresponsive properties of α, ω-di-[4-cyanophenyl-4’-(6-hexyloxy)-azo-benzene]-poly(N-isopropylacrylamide) in aqueous media. Chem. Commun., 2011, 47 (4), 1267 – 1269.