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...