Hasil untuk "Textile bleaching, dyeing, printing, etc."

Amarzaya Bazarvaani, Odonchimeg Genenbat, Dashjargal Arildii et al.

Driven by demand for sustainable textiles, this study evaluates red beetroot (Beta vulgaris L.) betalains as a natural dye for cashmere. We compared two dyeing approaches: conventional dyeing at pH 3.5 (acetate buffer), 85°C for 55 min (yielding yellow tones), and pre-functionalization with ethanol in acidic conditions at 25°C for 30 min followed by low-temperature dyeing (yielding red – violet tones). Optimization identified preferred conditions of 50°C, 5 wt.% initial dye concentration, pH 3.0, and 60 min. Betalains were extracted with 6% yield, and characterized by adsorption peaks at 530 nm and 480 nm, indicating betacyanins and betaxanthins. Adsorption followed pseudo-first-order kinetics and fit the Freundlich isotherm, implying heterogeneous, multi-stage adsorption with spontaneous tendencies (Freundlich n > 1). The process was endothermic, with adsorption capacity increasing with temperature, and the activation energy was 29.8 kJ mol−1, consistent with electrostatic and van der Waals interactions. Dyed cashmere retained the natural cuticle morphology, required no metallic mordants, and showed improved mechanical properties (breaking strength +3.8%, elongation +22.5%) and color fastness scores of 4–5. Results sipport betalains as an eco-friendly dye for high-quality cashmere.

Mohammad Shohag Babu, Tania Akther, Sk. Mohammad Raafi et al.

Gregory G. Guymon, Hao A. Nguyen, David Sharp et al.

The unique optical properties of quantum dots (QDs), size-tunable emission and high quantum yield, make them ideal candidates for applications in secure quantum communication, quantum computing, targeted single-cell and molecular tagging, and sensing. Scalable and deterministic heterointegration strategies for single QDs have, however, remained largely out of reach due to inherent material incompatibilities with conventional semiconductor manufacturing processes. To advance scalable photonic quantum device architectures, it is therefore crucial to adopt placement and heterointegration strategies that can address these challenges. Here, we present an electrohydrodynamic (EHD) printing model, single particle extraction electrodynamics (SPEED) printing, that exploits a novel regime of nanoscale dielectrophoretics to print and deterministically position single colloidal QDs. Using QDs solubilized in apolar solvents, this additive, zero-waste nanomanufacturing process overcomes continuum fluid surface energetics and stochastic imprecision that limited previous colloidal deposition strategies, achieving selective extraction and deposition of individual QDs at sub-zeptoliter volumes. Photoluminescence and autocorrelation function (g(2)) measurements confirm nanophotonic cavity-QD integration and single-photon emission from single printed QDs. By enabling deterministic placement of single quantum dots, this method provides a powerful, scalable, and sustainable platform for integrating complex photonic circuits and quantum light sources with nanoscale precision.

Aylin Ulman, Muhammet Uzun, Alexandra Ioanid

This study assesses the feasibility of utilizing an invasive and inedible pufferfish species ( Lagocephalus sceleratus ) for non-food purposes, aiming to help control its population in the Mediterranean Sea. Previous research suggests that the skin of the pufferfish holds promise for yielding valuable and environmentally friendly exotic leather. We investigate various tanning methods to convert pufferfish skin into leather, providing the first comparative analysis of its kind. Our primary focus is to characterize the properties of this leather and offer essential insights for its utilization across different product categories. Industry-standard tests were conducted to assess the quality of the leather, which was then compared with conventional leather. We illustrate how such products can be developed through interdisciplinary collaborations. Our findings clearly demonstrate the high potential, quality, and feasibility of converting invasive pufferfish skin into leather and related products, thus opening avenues for its integration into the fashion industry. Furthermore, we showcase the creation of leather accessories and shoes to highlight potential applications, alongside an analysis of sewing and processing capabilities. In conclusion, this study meticulously presents a successful case study for managing one of the most severe marine invasive species in the Mediterranean Sea under a blue economy framework, while also introducing it as a new textile option for the fashion industry as a novel eco-friendly exotic fish leather alternative.

Gerardo Díaz-Godínez

Currently, human life expectancy has increased considerably compared to that before the 19th century, however, the large world population and the enormous industrial and technological development have caused a serious problem of environmental pollution. The presence of large quantities of xenobiotic and recalcitrant compounds in the air, soil and water produce serious damage to the ecosystems and cause various diseases in humans such as neuronal damage, gastro-intestinal problems, partial paralysis, blindness and certain cancers of the skin, lung, liver, kidney and prostate, etc. (Mustafa and Najmaldin, 2024). For this reason, intense efforts have been made by the researchers worldwide to remediate the environment. Various physical, chemical and biological techniques have been developed for cleaning the environment and widely researched. Biological technique commonly termed as 'Bioremediation' involves the use of plants, animals and microorganisms that serve as bio-accumulators and effectively aid in the bioremediation of polluted environment. In bioremediation processes, algae, bacteria and fungi are mainly used, taking advantage of their metabolic capacities or enzymes produced by these organisms under controlled conditions, where in both cases the degradation or elimination of contaminants is sought to avoid the toxic or harmful effects on living beings(Bibbins-Martínez et al., 2023). Hydrosphere forms the major realm of the planet earth. Despite occupying 70% of the earth, only 2% is fresh water, and 0.036% is available since the rest is found in the glaciers at the poles and in inaccessible places such as subterranean rivers. Water pollution is a serious problem worldwide that needs urgent attention as well as effective solution. Anthropogenic activities are one of the major causes of environmental pollution. Regular and uncontrolled discharge of toxic compounds like pesticides, detergents, heavy metals, phenolic compounds, hydrocarbons, textile and food dyes, pharmaceutical and cosmetic wastes, etc., are contaminating the aquatic ecosystems. Fungi are efficient bio-remediators as well as bio-accumulators of toxic compounds present in the water bodies. Their remediation mechanisms involve biosorption, bioaccumulation and biodegradation (Legorreta-Castañeda et al., 2020; Bibbins-Martínez et al., 2023). Biosorption by fungi (whether alive or dead) is a process where contaminants have an affinity for one of the components of the cell wall such as glucans, chitins and mannans and functional groups such as phosphate, carboxyl, amino and thiol; the affinity can be physical and/or chemical, ion exchange, complexation, chelation and microprecipitation (Sadhasivam et al., 2009; Bibbins-Martínez et al., 2023). Bioaccumulation is based on active metabolic transport where contaminating compounds pass through the membrane into the cell, accumulating and, in the best of cases, gets metabolized (Volesky, 2007; Bibbins-Martínez et al., 2023). Biodegradation occurs mainly by enzymatic pathways, either by extracellular enzymes or by those involved in the fungal metabolism (Bibbins-Martínez et al., 2023). It is important to mention that fungi have been classified based on their capacity to degrade wood, like soft-rot fungi (degradation of starches, pectins, etc), brown-rot fungi (degrading even cellulose and hemicellulose) and white-rot fungi, which are capable of degrading cellulose, hemicellulose and lignin, since in addition producing a wide range of carbohydrases they also produce oxidases such as laccases and various peroxidases, which are among the most important enzymes due to their potential application in bioremediation processes. In view of the above and concerned about contributing to the solution of water bioremediation, I and my team have been working for last two decades in search of fungal strains, in particular Pleurotus genus that belong to the group of white-rot fungi and produces laccase enzymes, as well as establishing the cultivation conditions to increase their production. Laccases are enzymes that have been categorized in the group of multicopper blue oxidases, they are glycosylated and use oxygen as the final electron acceptor forming water. They eliminate hydrogen from the hydroxyl of methoxy-substituted monophenols, ortho- and para-diphenols, but they can also oxidize aromatic amines and non-phenolic compounds forming free radicals. These enzymes have a potential use in various bioremediation processes that include the elimination or removal of phenolic compounds and decolorization of dyes present in the industrial wastewater. They are used in several processes like bleaching of paper pulp, delignification, wine clarification, etc (Diaz-Godinez, 2011). Initially, we evaluated the laccase activity in ten strains of Pleurotus genus using three substrates (2,6-dimethoxyphenol, p-anisidine and o-tolidine), finding that the Pleurotus ostreatus ATCC 32783 strain was the one that presented the highest laccase activity both at intracellular and extracellular level (Tellez-Tellez et al., 2005). All the subsequent studies performed with this strain, cultured in both solid-state fermentation and submerged fermentation showed differences in their activity levels and number of isoenzymes depending on the culture system (Tlecuitl-Beristain et al., 2008; Téllez-Téllez et al., 2008; Díaz-Godínez et al., 2017). Studies on the effect of the pH of the culture medium on the activity of laccases have shown different patterns of production of laccase isoenzymes, with maximum activity at pH 4.5 (Díaz et al., 2011, 2013). In another study, the best culture temperature of the fungus for laccase production was observed at 25 0C (Montalvo et al., 2020). The presence of dyes in wastewater from textile industries represents one of the main sources of environmental pollution, so it is urgent to find solutions to this serious problem. In this sense, fungi have the potential capacity to discolor and degrade this type of compounds (Martinez-Berra et al., 2018). Based on the knowledge about the production of laccases by the ATCC 32783 strain, we separately evaluated the decolorization of textile dye, Remazol Brilliant Blue R and the degradation of the phenolic compound 2,6-dimethoxyphenol, on the submerged fermentation medium of Pleurotus ostreatus. At the same time, the activities of laccases, manganese peroxidase and veratryl alcohol oxidase, which are enzymes of the ligninolytic system of the fungus, were evaluated. It was observed that both the dye and the phenolic compound were eliminated from the culture medium due to the enzymatic action of Pleurotus ostreatus, which are promising results for application in bioremediation processes of water contaminated with these types of compounds (Grandes-Blanco et al., 2013). Subsequently, in an another study, Remazol Brilliant Blue R and Acetyl Yellow G dyes were added to the submerged fermentation medium of Pleurotus ostreatus, in order to determine their decolorization potential and capacity to induce laccase isoenzymes; their showed increased enzymatic activity, with Remazol Brilliant Blue R being the one to increase the laccase activity and the number of isoenzymes, concluding that the response of laccase production by Pleurotus ostreatus is different depending on the dye evaluated (Garrido-Bazán et al., 2016). In search of other fungi capable of decolorizing textile dyes, we isolated six strains from a textile industry effluent. There were three strains of Emmia latemarginata producing laccases and three strains of Mucor circinelloides producing tyrosinases; all the strains produced versatile peroxidase, manganese peroxidase and lignin peroxidase. The ability of the strains to decolorize the dyes Indigo, Remazol Yellow 145, Remazol Red 3B, Remazol Brilliant Blue R, Disperse Black 1, Disperse Yellow 3, Disperse Red 19 and Acetyl Yellow G was evaluated in Petri dishes with agar. All strains were able to decolorize all dyes at different levels. In submerged fermentation, two Remazol dyes (red and yellow) were less susceptible to decolorization, but total decolorization of the dyes Indigo and Remazol Brilliant Blue R was achieved by a strain of Emmia latemargina (Juárez-Hernández et al., 2021). To illustrate decolorization of textile dyes by fungi in the laboratory, Fig. 1 shows the four main stages of bioprocess using a basidiomycete. The first stage involves selection of the fungal strain based on its habitat, metabolic capacity and enzymatic activity, followed by isolation, identification and physiological and biochemical characterization thereafter decolorization studies are carried out looking for the conditions of maximum decolorization. The use of fungi and their enzymes in bioremediation process is a viable alternative, but despite the results obtained so far, there are still many challenges, including the scaling and design of processes that industries can adopt so that their discharges have less pollutants and consequently, the harmful effect on the environment is reduced for the benefit of ecosystems and humans. The great interest and effort of the scientific community seeking techniques for the recovery of the environment must be accompanied by mindful actions and fruitful activities, that is why it is emphasized that a healthy planet will not be one that is cleaned more or where bioremediation is more efficient, but one where it is less polluted, so society from different sectors must become aware and act to emit less pollutants.

Yayati Jadhav, Peter Pak, Amir Barati Farimani

Industry 4.0 has revolutionized manufacturing by driving digitalization and shifting the paradigm toward additive manufacturing (AM). Fused Deposition Modeling (FDM), a key AM technology, enables the creation of highly customized, cost-effective products with minimal material waste through layer-by-layer extrusion, posing a significant challenge to traditional subtractive methods. However, the susceptibility of material extrusion techniques to errors often requires expert intervention to detect and mitigate defects that can severely compromise product quality. While automated error detection and machine learning models exist, their generalizability across diverse 3D printer setups, firmware, and sensors is limited, and deep learning methods require extensive labeled datasets, hindering scalability and adaptability. To address these challenges, we present a process monitoring and control framework that leverages pre-trained Large Language Models (LLMs) alongside 3D printers to detect and address printing defects. The LLM evaluates print quality by analyzing images captured after each layer or print segment, identifying failure modes and querying the printer for relevant parameters. It then generates and executes a corrective action plan. We validated the effectiveness of the proposed framework in identifying defects by comparing it against a control group of engineers with diverse AM expertise. Our evaluation demonstrated that LLM-based agents not only accurately identify common 3D printing errors, such as inconsistent extrusion, stringing, warping, and layer adhesion, but also effectively determine the parameters causing these failures and autonomously correct them without any need for human intervention.

Daya Bandhu Ghimire, Pallab Shrestha

The development of a desktop Braille printing machine aims to create an affordable, user-friendly device for visually impaired users. This document outlines the entire process, from research and requirement analysis to distribution and support, leveraging the content and guidelines from the GitHub repository,https://github.com/fablabnepal1/Desktop-Braille-Printing-Machine.

Kefan Zhu, Bibhu Sharma, Phuoc Thien Phan et al.

Work related musculoskeletal disorders (WMSDs) are often caused by repetitive lifting, making them a significant concern in occupational health. Although wearable assist devices have become the norm for mitigating the risk of back pain, most spinal assist devices still possess a partially rigid structure that impacts the user comfort and flexibility. This paper addresses this issue by presenting a smart textile actuated spine assistance robotic exosuit (SARE), which can conform to the back seamlessly without impeding the user movement and is incredibly lightweight. The SARE can assist the human erector spinae to complete any action with virtually infinite degrees of freedom. To detect the strain on the spine and to control the smart textile automatically, a soft knitting sensor which utilizes fluid pressure as sensing element is used. The new device is validated experimentally with human subjects where it reduces peak electromyography (EMG) signals of lumbar erector spinae by around 32 percent in loaded and around 22 percent in unloaded conditions. Moreover, the integrated EMG decreased by around 24.2 percent under loaded condition and around 23.6 percent under unloaded condition. In summary, the artificial muscle wearable device represents an anatomical solution to reduce the risk of muscle strain, metabolic energy cost and back pain associated with repetitive lifting tasks.

Khorolsuren Tuvshinbayar, Nonsikelelo Sheron Mpofu, Thomas Berger et al.

Possibilities to perform 3D printing directly on textile fabrics have been investigated intensively during the last decade. Usually, fused deposition modeling (FDM) printing with often inexpensive 3D printers is applied in these experiments. Several studies revealed the influence of textile fabrics, FDM polymers and printing parameters, indicating that not all combinations of fabrics and printing materials are suitable for this task. Recently, first approaches to use stereolithography (SLA) or PolyJet Modeling (PJM) directly on textile fabrics have been reported. Here, the first comparison of the adhesion forces reached by FDM and SLA printing on different woven fabrics is shown, revealing significantly better adhesion for SLA printing.

Savita V. Kendre, Lehong Wang, Ethan Wilke et al.

Existing fluidic soft logic gates for the control of soft robots either rely on extensive manual fabrication processes or expensive printing techniques. In our work, we explore Fused Deposition Modeling for creating fully 3D printed fluidic logic gates. We print a soft bistable valve from thermoplastic polyurethane using a desktop FDM printer. We introduce a new printing nozzle for extruding tubing. Our fabrication strategy reduces the production time of soft bistable valves from 27 hours with replica molding to 3 hours with a FDM printer. Our rapid and cost-effective fabrication process for fluidic logic gates seeks to democratize fluidic circuitry for the control of soft robots.

Rey Fernando García-Méndez, Carlos Inocencio Cortés-Martínez, J.G. Carrillo et al.

Natural fibers are an attractive solution in the composite material industry, for achieving the biodegradability and sustainability that synthetic fibers do not offer. In this study, the effect of the alkali treatment (AT) on the physical properties, chemical composition, morphology, thermal behavior, and tensile strength of fibers extracted from Agave angustifolia Haw leaves was studied. Fibers were treated with 5% NaOH solution (v/v) for 10, 30, and 60 min. Tensile tests of single treated fibers (TF) were carried out at three-gauge lengths. The percentages of lignin and hemicellulose showed a decrease with AT which, in turn, induced a modification of morphological and crystalline structures. Thermal analysis revealed that, due to the presence of hemicellulose constituents, the untreated fibers (UF) had lower thermal stability than TF. Tensile tests revealed that the strength and strain decreased with the increase in the diameter and the test gauge length of the agave fibers.

P. Miladinova, Dimitrina Atanasova Todorova

Sam Keller, Matthew Stein, Ognjen Ilic

Additive manufacturing, such as 3D printing, offers unparalleled opportunities for rapid prototyping of complex three-dimensional objects, but typically requires simultaneous building of solid supports to minimize deformation and ensure contact with the printing surface. Here, we theoretically and experimentally investigate the concept of material extrusion on an "air bed", a judiciously engineered acoustic field that supports the material by contactless radiation force. We study the dynamics of polylactic acid filament (PLA), a commonly used material in 3D printing, as it interacts with the acoustic potential during extrusion. We develop numerical models to determine optimal transducer arrangements and printing conditions, and we build and demonstrate a concept prototype that integrates a commercial 3D printer and open-source control code. Our results point towards alternative, contactless support mechanisms with potential benefits such as fewer surface defects, less material waste, lower cost, and reduced manufacturing time. These features could become crucial as additive manufacturing continues to evolve into a foundational tool in engineering and beyond.

Vasily Lapidas, Alexey Zhizhchenko, Eugeny Pustovalov et al.

Security labels combining facile structural color readout and physically unclonable one-way function (PUF) approach provide promising strategy for fighting against forgery of marketable products. Here, we justify direct femtosecond-laser printing, a simple and scalable technology, for fabrication of high-resolution (12500 dots per inch) and durable PUF labels with a substantially large encoding capacity of 10$^{895}$ and a simple spectroscopy-free optical signal readout. The proposed tags are comprised of laser-printed plasmonic nanostructures exhibiting unique light scattering behavior and unclonable 3D geometry. Uncontrollable stochastic variation of the nanostructure geometry in the process of their spot-by-spot printing results in random and broadband variation of the scattering color of each laser printed "pixel", making laser-printed patterns unique and suitable for PUF labeling.

Gilda Santos, Rita Marques, Francisca Marques et al.

Nowadays, despite the evolution of personal protective equipment (PPE), the number of firefighters injured and burned during fire extinguishing operations is still very high, leading in some cases to loss of life. Therefore, the research and development of new solutions to minimize firefighters’ heat load and skin burns, with consecutive improvements of commercial firefighters’ suits, is of extreme importance. The integration of phase change materials (PCMs) in a protective clothing system has been used to significantly reduce the incoming heat flux from the fire environment. This study consists in the development of a protective clothing system composed by a vest, specially designed to protect the torso (back, chest and abdomen) with a layer of PCM pouches, to be worn over a fire-resistant jacket – selection and design based on numerical models’ predictions. Therefore, several mockups were made, varying the number of PCM pouches and their distribution in the vest, allowing the creation of air ducts to increase the breathability of the vest. The most promising solutions are being evaluated in a real controlled environment, at a Portuguese National School of Firefighters (ENB) simulation site, using a fire manikin and thermocouples to monitor vest temperature during heat and flame exposure, and consequently to verify PCMs influence in heat protection. Results regarding the development of a PCM vest will be presented, focusing on the integration of PCM pouches and the thermal performance of the most promising solutions.

Nágila F. Souza, Jéssica S. Almeida, José A. Pinheiro et al.

Plant fibers are excellent sources of biomacromolecules, but the extraction of these chemicals critically depends on pretreatments on the biomass. In this work, steam explosion followed by acetosolv or ethanosolv pulping were evaluated as pretreatments for cellulose nanocrystal and lignin extraction from oil palm mesocarp fibers. The steam explosion improves defibrillation of the biomass, deconstructs lignocellulosic material, facilitating the separation between lignin and polysaccharides by organosolv pulping. The effects of acetic acid or sodium hydroxide concentrations and reaction time for acetosolv or ethanosolv pulping were evaluated by a central composite design. Fibers and biomacromolecules were characterized using analytical methods, including SEM, TEM, DRX, zeta potential, and FTIR. The optimized conditions to obtain cellulose nanocrystals from bleached acetosolv fibers (CNCA) were 80% (w/w) acetic acid catalyzed with HCl 0.6% (w/w) for 35 min, while the optimized conditions from ethanosolv fibers (CNCE) were NaOH 4% (w/v) and ethanol 95% (v/v) for 60 min. The lignins obtained from both optimized conditions presented high purity. The acetosolv delignification was more effective to extract the insoluble lignin (yield of 36.7%) than ethanosolv (yield of 23.2%). The CNCA and CNCE presented, respectively, high crystallinity (68% and 56%) and good aspect ratio (26 and 25).

Mohammad Hosein Beheshti, Ali Khavanin, Ali Safari Varyani et al.

Both natural and synthetic fibers do not perform well at low frequencies and are also subjected to erosion, moisture, fire, etc., when used as an interior finish of room walls. To overcome these problems, micro-perforated plate with different thickness is used in a multilayer sound absorber configuration to improve its sound absorption. Firstly, the acoustic properties of five natural wastes including sheep wool, goat wool, camel wool as well as pith and fiber bundles of sugarcane bagasse were determined by using an impedance tube following ISO 10534–2. Secondly, the effect of Panel thickness was investigated. The maximum sound absorption coefficient (SAC) of natural waste materials is at middle to high-frequency range and this shifted to lower frequency as the porous layer thickness increases. The sound absorption performance depends on the thickness of perforated plate and porous layer in a compound sound absorber. It is observed that the using perforated plate in the front of low thickness porous materials significantly improve the SAC and absorption bandwidth. However, it should be noted that this reduces the SAC at high frequencies. Accordingly, the thick micro-perforated panels backed by porous layer are not recommended to control sounds with frequency higher than 3000 Hz.

Moussa Abbas, Zahia Harrache, Tounsia Aksil et al.

The adsorption of indigo carmine dye onto Activated Pomegranate Peels (APP) from aqueous solutions was followed in a batch system. The adsorbent was characterized by the BET method (specific surface area S BET : 51.0674 m 2 /g) and point of zero charge (pHpz = 5.2). However, some examined factors were found to have significant impacts on the adsorption capacity of pomegranate peels (APP) such as the initial dye concentration (10–60 mg/L), solution pH (2–12), adsorbent dose (1–10 g/L), agitation speed (100–600 rpm), and temperature (298–308 K). The best adsorption capacity was found at pH 2 with an adsorbent dose 1 g/L, an agitation speed 300 rpm and a contact time of 45 min. The adsorption mechanism of IC onto (APP) was studied by using the first-pseudo order, second-pseudo order, Elovich, and Webber-Morris diffusion models. The adsorptions kinetic were found to follow rather a pseudo-second order kinetic model with a determination coefficient ( R 2 ) of 0.999. The equilibrium adsorption data for IC onto (APP) were analyzed by the Langmuir, Freundlich, Elovich, and Temkin models. The results indicate that the Langmuir model provides the best correlation with capacities ( q max of 158.73 mg/g at 298 K). The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters like the free energy; enthalpy and entropy to predict the nature of adsorption process. The negative values Δ G ° and Δ H ° indicate that the overall adsorption is spontaneous and exothermic with a physisorption process. The adsorbent elaborated from pomegranate peels material was found to very effective and suitable for the removal of reactive dyes from aqueous solutions, due to its availability, low cost preparation, and good adsorption capacity.

Inga Lasenko, Dace Grauda, Dalius Butkauskas et al.

In this research, we focused on testing the physical and mechanical properties of the developed polyacrylonitrile (PAN) composite nanofibers with succinite (Baltic amber) and SiO₂ particles using standard methods of nanofiber testing (physical and mechanical properties). Polyacrylonitrile composite nanofibers (based on the electrospinning method) were coated on an aluminum substrate for structural investigation. SEM was used to determine the average fiber diameter and standard deviation. The mechanical properties of the fibers were determined using a universal testing machine (NANO, MTS). We observed that constant or decreased levels of crystallinity in the ultrafine composite nanofibers led to the preservation of high levels of strain at failure and that the strength of nanofibers increased substantially as their diameter reduced. Improvements in PAN composite nanofibers with succinite and SiO₂ nanopowder are feasible with continuous decreases in diameter. The drastically decreased strain at failure demonstrated a substantial reduction in viscosity (toughness) of the annealed nanofibers. Large stresses at failure in the as-spun nanofibers were a result of their low crystallinity. As a result, decreasing the diameter of PAN nanofibers from approximately 2 micrometers to 139 nanometers (the smallest nanofiber tested) resulted in instantaneous increases in the elastic modulus from 1 to 26 GPa, true strength from 100 to 1750 MPa, and toughness from 20 to 604 MPa.