Electron conductive self-assembled hybrid low-molecular weight glycolipid-nanosilver gels

TL;DR

This study presents a biobased glycolipid that self-assembles into hydrogels embedding silver nanoparticles, which can be controlled in size and shape, leading to conductive hybrid materials suitable for advanced applications.

Contribution

It introduces a novel biobased glycolipid that forms self-assembled hydrogels with embedded silver nanostructures, enabling controlled synthesis of conductive hybrid materials under mild conditions.

Findings

Silver nanoparticles of ~2.8 nm were stabilized within the hydrogel fibers.

Controlled reduction led to formation of silver nanowires with anisotropic coalescence.

Hydrogels with embedded silver nanowires exhibited measurable electronic conductivity.

Abstract

Low-molecular weight (LMW) hydrogels are gaining interest over macromolecular gels due to their reversible, dynamic and stimuli-responsive nature. They are potentially interesting functional materials for advanced applications such as catalysis, nanoelectronics or regenerative medicine. One common strategy to enhance the functional properties is to incorporate inorganic nanostructures. However, simultaneous control of the gel mechanics, shape and size of the nanostructures and functional properties is challenging. Here, a biobased, double amphiphilic, bolaform, single-glucose lipid (containing glucose and COOH in opposite directions) is able to coordinate silver ions, drive the formation of a self-assembled fibrous hydrogel and, after controlling the reduction time (seconds to hours) of the reduction process (NaBH4, ascorbate, $\gamma$-rays), stabilize Ag nanoparticles (NPs) of controlled size (2.8 nm $\pm$ 13%). The NPs are spontaneously embedded in the fibers' core following a two-dimensional anisotropic long-range order. Precise control of the reduction parameters (ascorbate) drives the formation of Ag nanowires, possibly due to an anisotropic coalescence process of the nanoparticles. Samples containing Ag nanowires have shown an electronic conductive response, observed with impedance spectroscopy. This works shows the potential of biological amphiphiles to develop under soft conditions (pseudo single step, water, room temperature) advanced hybrid organic/inorganic (O/I) materials with a multiscale structure, order and electron conductivity functionality