High water‐content thermoresponsive hydrogels via electrostatic macrocrosslinking of cellulose nanofibrils. Issue 21 (18th July 2016)

• Record Type: Journal Article
• Authors: Ingverud, Tobias; Larsson, Emma; Hemmer, Guillaume; Rojas, Ramiro; Malkoch, Michael; Carlmark, Anna
• Is Part Of: Journal of polymer science. Volume 54:Issue 21(2016)
• Page Start: 3415
• Page End: 3424
• Publication Date: 2016-07-18
• Subjects: ATRP -- cationic block copolymer -- cellulose nanofibrils -- hydrogels -- thermoresponsive; 547
• DOI: 10.1002/pola.28225
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: Atom transfer radical polymerization (ATRP) has been utilized to synthesize tri‐ and star‐block copolymers of poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) and quaternized poly(2‐(dimethylamino)ethyl methacrylate) (qPDMAEMA). The block copolymers, all with a minimum of two cationically charged blocks, were sequentially used for electrostatic macrocrosslinking of a dilute dispersion of anionic TEMPO‐oxidized cellulose nanofibrils (CNF, 0.3 wt%), forming free‐standing hydrogels. The cationic block copolymers adsorbed irreversibly to the CNF, enabling the formation of ionically crosslinked hydrogels, with a storage modulus of up to 2.9 kPa. The ability of the block copolymers to adsorb to CNF was confirmed by quartz crystal microbalance with dissipation monitoring (QCM‐D) and infrared spectroscopy (FT‐IR), and the thermoresponsive properties of the hydrogels were investigated by rheological stress and frequency sweep, and gravimetric measurements. This method was shown to be promising for the facile production of thermoresponsive hydrogels based on CNF. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2016, 54, 3415–3424 Abstract : Thermoresponsive, free‐standing hydrogels were produced from anionic TEMPO‐oxidized cellulose nanofibrils (CNF, 0.3 wt%) which were electrostatically crosslinked with cationic tri‐ and star‐block copolymers. Atom transfer radical polymerization (ATRP) was utilized to synthesize the block‐copolymers of poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) and quaternized poly(2‐(dimethylamino)ethyl methacrylate) (qPDMAEMA), starting from dual‐ or tetra‐functional initiators. The resulting hydrogels had a storage modulus of up to 2.9 kPa and water content up to 99.2 wt%.