title: Fibrillar networks of glycyrrhizic acid for hybrid nanomaterials with catalytic features.
abstract: Self-assembly of the naturally occurring sweetening agent, glycyrrhizic acid (GA) in water is studied by small-angle X-ray scattering and microscopic techniques. Statistical analysis on atomic force microscopy images reveals the formation of ultralong GA fibrils with uniform thickness of 2.5 nm and right-handed twist with a pitch of 9 nm, independently of GA concentration. Transparent nematic GA hydrogels are exploited to create functional hybrid materials. Two-fold and three-fold hybrids are developed by introducing graphene oxide (GO) and in situ-synthesized gold nanoparticles (Au NPs) in the hydrogel matrix for catalysis applications. In the presence of GO, the catalytic efficiency of Au NPs in the reduction of p-nitrophenol to p-aminophenol is enhanced by 2.5 times. Gold microplate single crystals are further synthesized in the GA hydrogel, expanding the scope of these hybrids and demonstrating their versatility in materials design.
authors.affiliation: Laboratory of Food & Soft Materials Science, Institute of Food, Nutrition & Health, Department of Health Sciences & Technology, ETH Zürich, Schmelzbergstrasse 9, LFO E23, 8092 Zürich (Switzerland).
authors.forename: Abhijit
authors.initials: A
authors.lastname: Saha
authors.forename: Jozef
authors.initials: J
authors.lastname: Adamcik
authors.forename: Sreenath
authors.initials: S
authors.lastname: Bolisetty
authors.forename: Stephan
authors.initials: S
authors.lastname: Handschin
authors.forename: Raffaele
authors.initials: R
authors.lastname: Mezzenga
mesh_terms: D000627:Aminophenols / Q000737:chemistry; D002384:Catalysis; D019695:Glycyrrhizic Acid / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D020100:Hydrogels; D053768:Metal Nanoparticles / Q000737:chemistry; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry*; D009596:Nitrophenols / Q000737:chemistry; D010084:Oxidation-Reduction; D053838:Scattering, Small Angle; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D000627:Aminophenols; D020100:Hydrogels; D009596:Nitrophenols; D019695:Glycyrrhizic Acid; D006046:Gold; D006108:Graphite; C026729:4-aminophenol; C024836:4-nitrophenol
keywords: glycyrrhizic acid; nanohydbrid hydrogels; self-assembly; statistical analysis; tuneable catalysis