Université de Fribourg

Structure−properties relationship in proton conductive sulfonated polystyrene−polymethyl methacrylate block copolymers (sPS−PMMA)

Rubatat, Laurent ; Li, Chaoxu ; Dietsch, Hervé ; Nykänen, Antti ; Ruokolainen, Janne ; Mezzenga, Raffaele

In: Macromolecules, 2009, vol. 41, no. 21, p. 8130–8137

We report on the dependence of proton conductivity on the morphologies of sulfonated polystyrene−poly(methyl methacrylate) (sPS−PMMA) diblock copolymers. Three different diblock copolymers of varying molecular weight and block volume fraction were studied, and for each one several sulfonation degrees of the PS block were considered. The investigation of the morphologies of the self-assembled...

Université de Fribourg

Direct imaging of nanoscopic plastic deformation below bulk Tg and chain stretching in temperature-responsive block copolymer hydrogels by Cryo-TEM

Nykänen, Antti ; Nuopponen, Markus ; Hiekkataipale, Panu ; Hirvonen, Sami-Pekka ; Soininen, Antti ; Tenhu, Heikki ; Ikkala, Olli ; Mezzenga, Raffaele

In: Macromolecules, 2008, vol. 41, no. 9, p. 3243–3249

This work describes the thermoresponsive transition in polystyrene-block-poly(N-isopropylacrylamide)-block-polystyrene (PS-block-PNIPAM-block-PS) triblock copolymer hydrogels, as observed by both direct and reciprocal space in-situ characterization. The hydrogel morphology was studied in both the dry and wet state, at temperatures below and beyond the coil−globule transition of PNIPAM, using...

Université de Fribourg

Phase behavior and temperature-responsive molecular filters based on self-assembly of polystyrene-block-poly(n-isopropylacrylamide)-block-polystyrene

Nykänen, Antti ; Nuopponen, Markus ; Laukkanen, Antti ; Hirvonen, Sami-Pekka ; Rytelä, Marjaana ; Turunen, Ossi ; Tenhu, Heikki ; Mezzenga, Raffaele ; Ikkala, Olli ; Ruokolainen, Janne

In: Macromolecules, 2007, vol. 40, no. 16, p. 5827 -5834

This work describes the synthesis of temperature-responsive polystyrene-block-poly(N-isopropylacrylamide)-block-polystyrene triblock copolymers, i.e., PS-b-PNIPAM-b-PS, their self-assembly and phase behavior in bulk, and demonstration of aqueous thermoresponsive membranes. A series of PS-b-PNIPAM-b-PS triblock copolymers were synthesized using...