Tannic acid (TA) complexation with poly(N-isopropylacrylamide) (PNIPAAm) microgels changed their morphology and temperature responsiveness, depending on TA concentration and pH (below the TA pK a ). Complexes prepared with a low TA content had higher low critical solution temperature than pure PNIPAAm microgels as a consequence of the hydrophilic character of TA; however, above a concentration threshold, TA physically cross-links the polymeric network, altering their morphology and suppressing the thermodynamically driven PNIPAAm coil-to-globule transition. DRIFT spectral analysis indicated that within PNIPAAm-TA complexes hydrogen bonds were established between PNIPAAm amide and TA phenolic (CdO 3 3 3 H-O and N-H 3 3 3 O-H) and ester (N-H 3 3 3 O-C) groups. At pH 4, H-bonding was more diverse and extensive than at pH 7; hence the complexes thermoresponsive behavior was altered at lower TA contents for the acidic pH. Above the TA pK a , H-bonding is destabilized and the complexes recovered their spherical morphology and the ability to respond to temperature stimulus, thus demonstrating a reversible process with pH.

Herein we describe the design and the assembly of temperature sensitive polysulfone (PS)/polyacrylonitrile (PAN) blend membranes using supercritical fluid technology. Blended membranes were prepared using the CO 2 -assisted phase inversion method, and their pores were coated with two thermoresponsive hydrogelspoly(N-isopropylacrylamide) (PNIPAAm) and poly(N,N′-diethylacrylamide) (PDEAAm). Permeation experiments of bovine serum albumin (BSA) and lysozyme (LYS) solutions were used to evaluate the performance and temperature-responsive behavior of coated membranes. While membranes coated with PNIPAAm presented similar protein permeation profiles at temperatures below and above its lower critical solution temperature, PDEAAm coating imparted a temperature-responsive behavior to PS/PAN (90:10) membranes and selective permeation of proteins with different sizes.

The production, characterization and anti-biofouling activity of 3D porous scaffolds combining different blends of chitosan and oxazoline-based antimicrobial oligomers is reported. The incorporation of ammonium quaternized oligo(2-oxazoline)s into the composition of the scaffold enhances the stability of the chitosan scaffold under physiological conditions as well as its ability to repel protein adsorption. The blended scaffolds showed mean pore sizes in the range of 18-32 μm, a good pore interconnectivity and high porosity, as well as a large surface area, ultimate key features for anti-biofouling applications. Bovine serum albumin (BSA) adhesion profiles showed that the composition of the scaffolds plays a critical role in the chitosan-oligooxazoline system. Oligobisoxazoline-enriched scaffolds (20% w/w, CB8020) decreased protein adsorption (BSA) by up to 70%. Moreover, 1 mg of CB8020 was able to kill 99.9% of Escherichia coli cells upon contact, demonstrating its potential as promising material for production of tailored non-fouling 3D structures to be used in the construction of novel devices with applications in the biomedical field and water treatment processes.