Biopolymer Optical Fibers From Cellulose for Sensing Applications

Description

Optical fibres (OFs) are the backbone of modern telecommunication infrastructure and are widely used in sensing applications. Glass optical fibres (GOFs) and polymer optical fibers (POFs) are the two main classes of commercial fibers. Although possessing excellent optical properties, both GOFs and POFs lack active sensing capability and that has led to the exploration of alternative materials for OF fabrication. Recently, cellulose has entered the OF domain as a novel candidate material [1-3]. Cellulose-based OFs offer exciting features such as active sensing capability with fast wetting and drying, renewability, biocompatibility, and biodegradability, which conventional OFs lack. Such features, especially biocompatibility, makes cellulose OFs attractive for biomedical applications.

In this work, we present the fabrication of OFs from carboxymethyl cellulose (CMC) and demonstrate the application of such OFs in various sensing systems. CMC OFs were prepared via dry-jet wet spinning of CMC hydrogels into a coagulation bath. The spun hydrogel fibers were crosslinked with Al3+ ions in wet-state and then dried to obtain strong (tensile strength ~150 MPa), flexible, and optically clear multimode OFs. The light transmission window for the CMC OFs was 550-1350 nm, wherein, the minimum attenuation was measured to be 1.6 dB.cm-1 (at 637 nm), meaning CMC OFs have good waveguiding properties in the visible (red) to near infrared range. Further, exploiting the rapid moisture sorption of CMC, we demonstrated respiratory rate monitoring with CMC OFs. A touch sensor was also prepared. Additionally, we demonstrated high-speed (150 Mbit/s) optical signal transmission through CMC fibers in both air and water media, indicating potential applications involving bodily fluids. Our work shows the technical potential of cellulose optical fibers in advanced sensing applications, for instance in environmental sensing and in the biomedical domain.

Period	18 Sept 2023
Event title	8th EPNOE International Polysaccharides Conference: EPNOE Graz 2023
Event type	Conference
Location	Graz, AustriaShow on map
Degree of Recognition	International