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We report a theoretical and experimental investigation of fardetuned intramodal four wave mixing (FWM) in the fundamental mode of optical microfibers (OMF) depending on their diameter. We demonstrate that the signal wavelength can be tuned over a wide spectral range simply by varying the OMF diameter. Using a pump at 1064 nm, signal wavelengths ranging from around 750 to 950 nm are generating by adjusting the OMF diameter from approximately 8.5 to 6.5 µm.

We present measurements of the evolution of the core and cladding diameters in tapered silica microfibers by LC-OCT. The results will help to refine the models of propagation of modes in tapers.

With the aim of identifying new sources for cellulose manufacturing, post-harvest tomato plant residue (TPR) was proposed in this study as a viable and sustainable source for the extraction of cellulose derivatives, namely cellulose microfibers (CMF) and cellulose nanocrystals (CNC). Pure CMF with an average diameter of 20 µm were successfully produced by subjecting the raw TPR to chemical treatments and then characterized in terms of their morphology and physico-chemical characteristics. By subjecting CMF to sulfuric, phosphoric and citric/hydrochloric acid hydrolysis, sulfated CNC (S-CNC), phosphorylated CNC (P-CNC) and carboxylated CNC (C-CNC) have been successfully produced. This was done to produce CNC with different characteristics and surface functionalities depending on the inserted functional groups during the acid hydrolysis process. By using several characterization techniques, it was found that all the extracted CNC characterized by cellulose I structure, with a crystallinity index of 81–89, 81 and 78%, an aspect ratio of 40–49, 98 and 67 and zeta potential of − 27.8 to − 37.3, − 36.9 and − 22.3 mV for S-CNC, P-CNC and C-CNC, respectively. The determined thermal stability of all extracted CNC is relatively higher than that generally obtained for S-CNC from other sources, which suffer from limited thermal stability. The produced CNC with different surface functionalities formed stable colloidal suspensions in polar solvents such as water and dimethyl sulfoxide. The production of CMF and CNC from this underutilized waste has the potential to add value to the post-harvest tomato plant, which is produced annually as waste in vast quantities throughout the world, in addition to significantly reducing the volume of cumulative waste in the environment.

In this work, cellulose microfibers (CMFs) and cellulose nanocrystals (P-CNCs) having phosphoric groups on their surfaces were prepared by phosphorylation of cellulose extracted from Giant Reed plant, using ammonium dihydrogen phosphate (NH4H2PO4) in a water-based urea system and phosphoric acid (H3PO4) without urea as phosphorous agents, respectively. Phosphorylated samples were studied in terms of their charge content, chemical structure, crystallinity, morphology, and thermal stability using several characterization techniques. Conductometric titration results showed higher charge content after phosphorylation with urea for P-CMFs about 3133 mmol kg−1, while without urea P-CNCs exhibited 254 mmol kg−1. FTIR analysis confirmed the total removal of non-cellulosic compounds from microfibers’ surface and their partial oxidation after phosphorylation. XRD analysis proved that the P-CMFs and P-CNCs exhibited cellulose I structure, with a crystallinity index of 70 and 83%, respectively. SEM and AFM observations showed micro-sized and needle-like morphologies for P-CMFs and P-CNCs with an average diameter of 15 µm and 20.5 nm, respectively. The thermal properties of P-CMFs indicate early dehydration with high char formation, while the high thermal stability of P-CNCs (Tmax = 352 °C) was similar to that of microcrystalline cellulose. The present work showed new routes for preparing phosphorylated micro- and nano-cellulose from a new natural source, having new functions that benefit various applications.Graphic abstract

The development of flexible and stretchable wearable electronics has significantly advanced smart fabrics, biomedical devices, and healthcare technologies. However, these devices often face challenges from mechanical deformations that disrupt signals, emphasizing the need for strain‐insensitive architectures to maintain functionality under varying strain conditions. Progress in this field relies on multifunctional, strain‐insensitive microfibers and nanofibers (NFs) to ensure consistent performance while minimizing signal interference caused by mechanical stress. This review highlights the advantages of fibers for flexible, stretchable, and strain‐insensitive wearable electronics, analyzing materials, fabrication methods, and design strategies that optimize strain insensitivity in single free‐standing microfibers (SFMs) and NF‐based devices. It emphasizes maintaining mechanical and electrical stability under large strains through strategic material selection, advanced fiber spinning techniques, and innovative structural designs. While emphasizing SFMs, this review also provides a concise exploration of the role of NFs within this context. The applications of SFMs in wearable electronics, particularly as conductors, sensors, and components in smart textiles, are discussed with an emphasis on strain insensitivity. The review concludes by addressing challenges in this evolving field of wearable electronics and outlining future research directions, offering insights to drive innovations in fiber‐based wearable electronics for reliable, lightweight, breathable, user‐friendly, and high‐performance wearable devices. This review highlights the development of strain‐insensitive, flexible, and stretchable wearable electronics using micro‐ and nanofiber‐based approaches. Emphasizing the role of single free‐standing microfibers (SFMs) and nanofibers (NFs), it explores materials, fabrication techniques, and innovative architectures that maintain functionality under mechanical stress. The article provides insights into applications across lightweight wearable sensors, smart textiles, and healthcare devices, focusing on the critical advances and challenges shaping future wearable electronics.

Microfibers and microplastics originating from wastewater treatment plant (WWTP) effluents are significant pollutants in freshwater sources and marine environments. This research investigated the biodegradation of cotton microfibers generated from bleached cotton jersey knit fabric and commercially available flushable wipes, polypropylene-based (PP) nonwoven wipes containing a cellulose component, and tissue paper. Biodegradation was tested in wastewater treatment plants (WWTP) solids, seawater, and lakewater according to the ISO 14852 and ASTM D6691 standard methods in an ECHO respirometer. Degradation experiments continued until a plateau in CO2 emissions was reached, and the final biodegradation extent was calculated relative to the theoretical CO2 produced based on elemental analysis. The results showed that the cotton and other cellulosic materials/components biodegrade to a great extent, as expected for all conditions, whereas the PP did not degrade. In general, for the cellulose polypropylene composite wipes, the cellulose biodegraded readily; the presence of the PP did not hinder the cellulose biodegradation.

Microfibers and microplastics originating from wastewater treatment plant (WWTP) effluents are significant pollutants in freshwater sources and marine environments. This research investigated the biodegradation of cotton microfibers generated from bleached cotton jersey knit fabric and commercially available flushable wipes, polypropylene-based (PP) nonwoven wipes containing a cellulose component, and tissue paper. Biodegradation was tested in wastewater treatment plants (WWTP) solids, seawater, and lakewater according to the ISO 14852 and ASTM D6691 standard methods in an ECHO respirometer. Degradation experiments continued until a plateau in CO2 emissions was reached, and the final biodegradation extent was calculated relative to the theoretical CO2 produced based on elemental analysis. The results showed that the cotton and other cellulosic materials/components biodegrade to a great extent, as expected for all conditions, whereas the PP did not degrade. In general, for the cellulose polypropylene composite wipes, the cellulose biodegraded readily; the presence of the PP did not hinder the cellulose biodegradation.

The surface of pure polytetrafluoroethylene (PTFE) microfibers was modified with ZnO and graphene (G), and the composite was studied using ATR-FTIR, XRD, and FESEM. FTIR results showed that two significant bands appeared at 1556 cm−1 and 515 cm−1 as indications for CuO and G interaction. The SEM results indicated that CuO and G were distributed uniformly on the surface of the PTFE microfibers, confirming the production of the PTFE/CuO/G composite. Density functional theory (DFT) calculations were performed on PTFE polymer nanocomposites containing various metal oxides (MOs) such as MgO, Al2O3, SiO2, TiO2, Fe3O4, NiO, CuO, ZnO, and ZrO2 at the B3LYP level using the LAN2DZ basis set. Total dipole moment (TDM) and HOMO/LUMO bandgap energy ΔE both show that the physical and electrical characteristics of PTFE with OCu change to 76.136 Debye and 0.400 eV, respectively. PTFE/OCu was investigated to observe its interaction with graphene quantum dots (GQDs). The results show that PTFE/OCu/GQD ZTRI surface conductivity improved significantly. As a result, the TDM of PTFE/OCu/GQD ZTRI and the HOMO/LUMO bandgap energy ΔE were 39.124 Debye and ΔE 0.206 eV, respectively. The new electrical characteristics of PTFE/OCu/GQD ZTRI indicate that this surface is appropriate for electronic applications.

Microfibers, as emerging contaminants, pose a growing threat to the global environment. Microfiber pollution has been one of the hot research topics in environmental science. However, there is no consensus on microfiber definition from ecological and environmental perspectives. The underestimated sources, the distribution in the ocean and the atmosphere, the transport pathway, the potential human exposure, and mitigation strategies of microfibers from a global perspective have not been systemically discussed. So, we aim to discuss and analyze these concerns in this review. Firstly, the definition of microfiber pollutants from the ecological and environmental perspectives is proposed. Secondly, the largest source and some emerging sources of microfibers on the Earth have been explored. Thirdly, the distribution and transmission path of microfibers in the ocean and the atmosphere are discussed. Fourthly, the exposure path of microfibers to the human body is analyzed. Lastly, some applicable measures to control microfiber pollution are proposed from global environmental sustainable development perspectives.