Ioncell-F technology developed at Aalto University in collaboration with the University of Helsinki converts wood into textiles without any harmful chemicals. It is an environmentally friendly alternative to the water-intensive cotton production. In addition, the process may revolutionize the recycling of textile waste, as waste cotton can get a new life as high-quality luxury fibers.


What is Ioncell-F?

Ioncell-F is a new technology for producing man-made cellulosic textile fibers. Ioncell-F process is developed at Aalto University by the researchs of Prof. Herbert Sixta's group, and it uses a novel solvent, ionic liquid, invented at University of Helsinki by Prof. Ilkka Kilpeläinen's group.

Why Ioncell-F?

Demand for textile fibers is rapidly increasing because of the population growth and an improved standard of living. The future demand for textiles cannot be met by increasing the production of  cotton due to the large land area required for farming and the amount of water required for irrigation. Therefore, sustainable man-made fibers are needed to substitute cotton. 

Currently, there are two main man-made cellulose fibers (MMCF) on the market: viscose and lyocell (Tencel®). Production of viscose requires the use of carbon disulfide, a very toxic chemical. The solvent applied in the production of Tencel® fibers, NMMO, also has an intrinsic shortcoming: its chemical and thermal instability, causing a risk of dangerous runaway reactions.

The ionic liquid used in the Ioncell-F process is an environmentally friendly and inherently safe alternative to the solvents used in current man-made cellulosic fiber production processes.

Ioncell-F bowtie and handkerchief (photo: Eeva Suorlahti)

A woven bow tie and a handkerchief designed and made by Eveliina Netti.

Raw materials

The most common cellulose feedstocks for production of man-made cellulosic fibers is dissolving pulp. In addition to dissolving pulp, Ioncell-F process can utilize paper grade pulp from the kraft pulping process, as well as waste paper and cardboard, or waste cotton.

Ioncell-F fabrics (photo: Eeva Suorlahti)

Vivid, natural colors produced by using cardboard as a rawmaterial and lignin as an additive in the production of Ioncell-F fibers.

Ionic liquids

Ionic liquids are salts that have a melting point below 100 °C. The cellulose dissolving capability of ionic liquids has been known since 1930's, but the dissolution mechanism is still not fully understood. Of the numerous different ionic liquids tested over the years, only few have found to have excellent properties for the fiber spinning.

Properties of Ioncell-F fibers

Ioncell-F fibers feel soft and are strong even when wet. The fiber properties of Ioncell-F are equal or better than present viscose and Tencel®-fibers. Because of their high tenacity, Ioncell-F fibers are also promising for technical applications, e.g. for composites.

Ioncell cellphone cover (photo: Harri Santamala)

A phone case made of a composite of Ioncell-F fibers and epoxy resin.

Ioncell-F process

Ioncell-F fibers are produced using a Lyocell-type spinning process. There are three main steps in the fiber production process: cellulose dissolution, fiber spinning and recovery of the solvent.

Dissolution of cellulose

Ioncell-F is based on the direct dissolution of cellulose. The direct dissolution reduces the number of process steps in comparison to e.g. viscose process, in which cellulose has to be first converted to a soluble derivative.

In the dissolution step, pulp is mixed with the ionic liquid. Due to the high viscosity of the  mixture, the mixing is carried out in a kneader reactor. The resulting cellulose solution is called spinning dope.

Ioncell spinning (photo: Anni Hanén)

Fiber spinning  

Ioncell-F fibers are produced using dry-jet wet spinning. In this spinning technique, the cellulose solution is extruded through a spinneret forming fluid filaments, which then pass through an air gap into a coagulation bath. The coagulation bath is filled with water, an anti-solvent, and thus cellulose is regenerated. The formed fiber filaments are collected for downstream processing.

The strength of the fibers arises from the use of air gap, in which the fluid filaments are stretched. Most of the orientation of the cellulose chains occurs at this stage, which affects the fiber properties.

The downstream processing of fibers includes cutting the filaments to staple fibers, opening of the fibers, washing and surface treatment. After that, the fibers can be converted into yarns by a yarn production process that includes carding and spinning.

Solvent recovery

For a sustainable process, it is necessary to have a closed solvent and water loop in the production of Ioncell-F.

During the fiber spinning, ionic liquid is dissolved in water in the spin bath, and will be recovered as an aqueous solution. The ionic liquid is then separated from water and purified to prevent accumulation of soluble impurities in the closed solvent loop.

The research on the recovery and purification of ionic liquid is currently on-going.


Watch the video to see all the steps of the Ioncell-F process.

From birch to catwalk - in collaboration with Marimekko®

Allu dresse by Marimekko made of Ioncell-F

The first Ioncell-F garment, Allu dress designed by Tuula Pöyhönen, was presented on the occasion of Marimekko®’s fashion show in Helsinki Central Railway Station’s ticket hall on March 13, 2014.


Ioncell-F team

  • Prof. Herbert Sixta
  • Michael Hummel, Staff Scientist
  • Marja Rissanen, Research Fellow
  • Shirin Asaadi, PhD candidate
  • Yibo Ma, PhD candidate
  • Sanna Hellstén, Postdoctoral researcher
  • Simone Haslinger, PhD candidate
  • Harri Santamala, PhD candidate
  • Sherif Elsayed, PhD candidate
  • Leena Katajainen, PhD candidate
  • Mikaela Trogen, PhD candidate
  • Hilda Zahra, PhD candidate
  • Daisuke Sawada, Postdoctoral researcher
  • Kaniz Moriam, PhD candidate
  • Chamseddine Guizani, Postdoctoral researcher
  • Joanna Witos, Postdoctoral researcher

The development of Ioncell-F is a very cross-disciplinary project. We work in a close collaboration with


Recycling of textiles using Ioncell technology (photo: Eeva Suorlahti)

Recycling of cotton waste using Ioncell-F. The original colors of the fabric can stay in the new fibres, which reduces the need of dyeing. Aalto CHEMARTS / Senja Smirnova.

Ioncell-F publications

Scientific articles in peer-review journals


Ma, Y.; Stubb, J.; Kontro, I.; Nieminen, K.; Hummel, M.; Sixta, H. 2018, Filament spinning of unbleached birch kraft pulps: effect of pulping intensity on the processability and the fiber properties. Carbohydrate Polymers, 179, 145-151.

Asaadi, S.; Hummel, M.; Ahvenainen, P.; Gubitosi, M.; Olsson, U.; Sixta, H. 2018, Structural analysis of Ioncell-F fibres from birch wood. Carbohydrate Polymers, accepted.


Ma, Y., Hummel, M.; Kontro, I.; Sixta, H. 2017, High performance man-made cellulosic fibres from recycled newsprints. Green Chem., accepted.


Asaadi, S.; Hummel, M.; Hellsten, S.; Härkäsalmi, T.; Ma, Y.; Michud, A.; Sixta, H. 2016, Renewable High-Performance Fibers from the Chemical Recycling of Cotton Waste Utilizing an Ionic Liquid, ChemSusChem 9(22): 3250-3258.

Bulota, M.; Michud, A.; Hummel, M.; Hughes, M.; Sixta, H. 2016, The effect of hydration on the micromechanics of regenerated cellulose fibres from ionic liquid solutions of varying draw ratios, Carbohydr. Polym. 151: 1110-1114.

Michud, A.;  Hummel, M.; Sixta, H. 2016, Influence of process parameters on the structure formation of man-made cellulosic fibers from ionic liquid solution, J. Appl. Polym. Sci. 133 (30): 43718.

Michud, A.; Tanttu, M.; Asaadi, S.; Ma, Y.; Netti, E.; Kääriainen, P.; Persson, A.; Berntsson, A.; Hummel, M.; Sixta, H. 2016, Ioncell-F: ionic liquid-based cellulosic textile fibers as an alternative to viscose and Lyocell, Textile Research Journal 86 (5): 543-552.

Hauru, L.K.J.; Hummel, M.; Nieminen, K.; Michud, A.; Sixta, H, 2016, Cellulose regeneration and spinnability from ionic liquids, Soft Matter 12 (5): 1487-1495.

Ma, Y.; Hummel, M.; Määttänen, M.; Särkilahti, A.; Harlin, A.; Sixta, H. 2016, Upcycling of waste paper and cardboard to textiles, Green Chemistry 18 (3): 858-866.

Santamala, H.; Livingston, R.; Sixta, H.; Hummel, M.; Skrifvars, M.; Saarela, O. 2016, Advantages of regenerated cellulose fibres as compared to flax fibres in the processability and mechanical performance of thermoset composites. Composites, Part A: Applied Science and Manufacturing, 84: 377-385.

Hummel, M.; Michud, A.; Tanttu, M.; Asaadi, S.; Ma, Y.; Hauru, L.K.J.; Parviainen, A.; King, A.W.T.; Kilpelainen, I.; Sixta, H. 2016, Ionic liquids for the production of man-made cellulosic fibers - opportunities and challenges. Advances in Polymer Science 271: 133-168.

Holding, A.J.; Mäkelä, V.; Tolonen,L.; Sixta, H.; Kilpelainen, I.; King, A.W.T., 2016. Solution-state one- and two-dimensional NMR spectroscopy of high-molecular-weight cellulose. ChemSusChem 9(8): 880-892.

Stepan, A.M.; Michud, A.; Hellsten, S.; Hummel, M.; Sixta, H., 2016. IONCELL-​P&F: Pulp Fractionation and Fiber Spinning with Ionic Liquids. Ind. Eng. Chem. Res.  55(29): 8225-8233.

Byrne, N.; Setty, M.; Blight, S.; Tadros, R.; Ma, Y.; Sixta, H.; Hummel, M. 2016, Cellulose-Derived Carbon Fibers Produced via a Continuous Carbonization Process: Investigating Precursor Choice and Carbonization Conditions. Macromolecular Chemistry and Physics 217: 2517-2524.

Wanasekara, N.D.; Michud, A.; Zhu, Chenchen, Rahatekar, S.; Sixta, H.; Eichhorn, St.J. 2016, Deformation mechanism in ionic liquid spun cellulose fibres. Polymer 99: 222-230.


Ma, Y.; Asaadi, S.; Johansson, L.-S.; Ahvenainen, P.; Reza, M.; Alekhina, M.; Rautkari, L.; Michud, Anne; Hauru, L.; Hummel, M.; Sixta, H. 2015, High-Strength Composite Fibers from Cellulose-Lignin Blends Regenerated from Ionic Liquid Solution, ChemSusChem 8 (23): 4030-4039.

Michud, A., Hummel, M.; Haward, S.; Sixta, H. 2015, Monitoring of cellulose depolymerization in 1-ethyl-3-methylimidazolium acetate by shear and elongational rheology. Carbohydrate Polymers 117(6): 355–363.

Sixta, H.; Michud, A.; Hauru, L.; Asaadi, S.; Ma, Y.; King, A.W.T.; Kilpeläinen, I.; Hummel, M. 2015, Ioncell-F: A High-strength regenerated cellulose fibre, Nordic pulp & paper research journal 30 (1): 43-57.

Michud, A.; Hummel, M.; Sixta, H. 2015, Influence of molar mass distribution on the final properties of fibers regenerated from cellulose dissolved in ionic liquid by dry-jet wet spinning, Polymer 75 (28 September 2015): 1-9.

Hummel, M.; Michud, A.; Tanttu, M.; Asaadi, S.; Ma, Y.; Hauru, L.K.J.; Parviainen, A.; King, A.W.T.; Kilpelainen, I.; Sixta, H. 2015, Ionic liquids for the production of man-made cellulosic fibers - opportunities and challenges, Advances in polymer science (24 April 2015): 1-36.

Hummel, M.; Michud, A.; Asaadi, S.; Ma, Y.; Sixta, H.; Tanttu, M.; Netti, E. 2015, High-tenacity textile cellulose fibers from ionic liquid solutions, Chemical Fibers International, 65 (2): 105-107.

Wawro D.; Steplewski, W.; Madaj, W.; Michud, A.; Hummel, M.; Sixta, H. 2015, Impact of water in the casting of cellulosic film from ionic liquid solutions. Fiber&Textiles in Eastern Europe 23(4): 25-32.


Hauru, L.K.J.; Hummel, M.; Michud, A.; Sixta, H. 2014, Dry jet-wet spinning of strong cellulose filaments from ionic liquid solution, Cellulose, 21 (6), 4471-4481.

Wawro, D.; Hummel, M.; Michud, A.; Sixta, H. Strong cellulose film cast from ionic liquid solutions. Fibres&Textiles in Eastern Europe (2014), 22(3), 35-42.


Parviainen, A.; King, A.T.W.; Mutikainen, I., Hummel, M.; Selg, Ch., Hauru, L.K.J., Sixta, H. 2013, Predicting cellulose solvating capabilities of acid-based conjugate ionic liquids. ChemSusChem  6(11): 2161-2169.


King, Alistair W.T.; Parviainen, A.; Karhunen,P.; Matikainen,J.; Hauru,L.K.J:; Sixta, H.; Kilpelainen,I. 2012, Relative and inherent reactivities of imidazolium-based ionic liquids: the implications for lignocellulose processing applications. RCS Advances 2(21): 8020-8026.

Hauru, L.K.J.;Hummel, M.;King, A.W.T.;Kilpeläinen, I.;Sixta, H. 2012, Role of solvent parameters in the regeneration of cellulose from ionic liquid solutions, Biomacromolecules 13 (9): 2896-2905.

Doctoral theses

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Ioncell-F in news and blogs

Ioncell-F in the TV series "Suomen tulevaisuus" in Spring 2016:

Ioncell-F projects

Ongoing projects

  • Trash-2-Cash (EU Horizon 2020)
  • WoCaFi - Unlocking the Entire Wood Matrix for the next Generation Carbon Fibers (ERC)
    • This project financed through an ERC-Starting Grant aims at the production of fully bio-based carbon fibers from wood-derived biopolymers. High performance composite fibers comprising cellulose, hemicellulose and lignin are spun through the Ioncell-F technology to yield endless filaments of highest uniformity and pronounced lateral polymer orientation in the fiber matrix. The filaments are converted to carbon fibers in collaboration with Deakin University and Carbon Nexus, Australia. The pyrolysis reactions and structure transformation of the precursor filaments are studied amongst others by STA-FTIR/MS, Raman spectroscopy, X-ray scattering techniques to elucidate the carbonization and graphitization mechanisms of a multi-component polymer matrix.
    • Current team members: Michael Hummel (PI), Daisuke Sawada (postdoctoral researcher), Mikaela Trogen (PhD candidate), Hilda Zahra (PhD candidate).
  • DWoC 2.0 - Design Driven Value Chains in the World of Cellulose (Tekes)
  • SolvRec (Tekes)
  • iCom (Tekes TUTL)
  • TeKiDe (ERDF)

Past projects

Want to know more about Ioncell-F?

We are planning to scale-up the Ioncell-F. If you are interested to invest, please read more at

If you are interested to hear more about Ioncell-F, please contact us.

Contact information

Professor Herbert Sixta
Aalto University School of Chemical Engineering
tel. +35850 3841764
herbert.sixta [at] aalto [dot] fi

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