Responsive Adsorption of N-Isopropylacrylamide Based Copolymers on Polymer Brushes

Polymers

Guillaume Sudre¹  Fabrice Cousin²  Elodie Siband³  Yvette Tran³  Dominique Hourdet³  Bruno Gallas⁴ 

[1] Ingénierie des Matériaux Polymères, Université Claude Bernard Lyon 1, Université de Lyon, CNRS UMR 5223, 69100 Villeurbanne, France;Laboratoire Léon Brillouin, Université Paris-Saclay, CEA-CNRS, Saclay, 91191 Gif-sur-Yvette CEDEX, France;Soft Matter Sciences and Engineering, ESPCI Paris, PSL Université, Sorbonne Université, CNRS, 10 rue Vauquelin, F-75005 Paris, France;Sorbonne Université, CNRS-UMR 7588, Institut des NanoSciences de Paris, INSP, 4 place Jussieu, F-75005 Paris, France;

关键词: responsive brushes;    temperature-responsive;    ph-responsive;    swelling;    adsorption;    complexation;    scaling laws;    density profile;    neutron reflectivity;   

DOI  :  10.3390/polym12010153

来源: DOAJ

【 摘 要 】

We investigate the adsorption of pH- or temperature-responsive polymer systems by ellipsometry and neutron reflectivity. To this end, temperature-responsive poly (N-isopropylacrylamide) (PNIPAM) brushes and pH-responsive poly (acrylic acid) (PAA) brushes have been prepared using the “grafting onto” method to investigate the adsorption process of polymers and its reversibility under controlled environment. To that purpose, macromolecular brushes were designed with various chain lengths and a wide range of grafting density. Below the transition temperature (LCST), the characterization of PNIPAM brushes by neutron reflectivity shows that the swelling behavior of brushes is in good agreement with the scaling models before they collapse above the LCST. The reversible adsorption on PNIPAM brushes was carried out with linear copolymers of N-isopropylacrylamide and acrylic acid, P(NIPAM-co-AA). While these copolymers remain fully soluble in water over the whole range of temperature investigated, a quantitative adsorption driven by solvophobic interactions was shown to proceed only above the LCST of the brush and to be totally reversible upon cooling. Similarly, the pH-responsive adsorption driven by electrostatic interactions on PAA brushes was studied with copolymers of NIPAM and N,N-dimethylaminopropylmethacrylamide, P(NIPAM-co-MADAP). In this case, the adsorption of weak polycations was shown to increase with the ionization of the PAA brush with interactions mainly located in the upper part of the brush at pH 7 and more deeply adsorbed within the brush at pH 9.

【 授权许可】

Unknown