Department of Bioproducts and Biosystems

Biobased Materials Structure

The Biobased Materials Structure (BioMatS) group, led by Academy of Finland Research Fellow Paavo Penttilä, focuses on structural characterization of biobased materials, especially with X-ray and neutron scattering. The group’s multidisciplinary expertise evolves around applying small and wide-angle X-ray and neutron scattering on wood and other (ligno)cellulosic materials. Understanding the structure of biobased materials and developing methods for their characterization is fundamental to their utilization for sustainable applications.
Colour photo of wood chips and samples on textured surfaces, in a petri dish and a closed test tube
Photo of wood samples by Research Fellow Paavo Penttilä

Research topics

  • Nanoscale structural characterization of biobased materials

  • Development of X-ray and neutron scattering data analysis

  • Wood nanostructure and moisture interactions

News and events

  • Welcome to our two new members: postdoc Tomoko Kuribayashi and Master's thesis worker Janita Makkonen!
  • New project "WoodCensus", funded by the Research Council of Finland, started in January 2024
  • Group leader Paavo Penttilä received the Hayashi Jisuke award by The Cellulose Society of Japan, see news item

Ongoing research projects

Neural networks for X-ray scattering analysis of wood materials (NNxWOOD)

Illustration of wood structure and anatomy cube, synchrotron, x-ray of wood, x-ray scattering data brought together with an AI "brain"

This Academy of Finland Research Fellow project (2021–2026) aims to develop new machine learning based methods for analysing X-ray scattering data from wood materials. A detailed picture of the structure of wood cell walls is highly desired to accelerate the development of new, sustainable applications from this abundant renewable raw material. Recently developed imaging techniques based on X-ray scattering offer unprecedented possibilities for studying the hierarchical structure of wood, but the development of new automated procedures for the data analysis is necessary.

Follow on X (Twitter): #NNxWOOD

Automatized reconstruction of wood cell wall nanostructure from X-ray scattering patterns (WoodCensus)

Graphical abstract of WoodCensus

This collaborative project between our group and VTT Technical Research Centre of Finland is funded by the Research Council of Finland for 2024–2026. The project develops a workflow for automatized analysis of small-angle scattering data from wood materials. The method generates three-dimensional reconstructions of the cell wall nanostructure based on scattering patterns. It aims to make the use of scattering methods more efficient, to digitalize the nanostructure of wood cell walls, and to promote the utilization of high-performance computing in the field of bio-based materials.

Simulation-assisted scattering analysis of moisture-induced swelling in wood microfibril bundles (SASAMIS)

Illustration featuring Molecular models of microfibril bundles in brown and purple, to predict X-ray scattering patterns of wood samples, to refine the molecular models; line graph

The interpretation of X-ray scattering data from wood currently depends on highly approximate models of cellulose microfibrils and their bundles. By coupling molecular simulations with tailored scattering measurements, we can improve the resolving power of both methods, and gain fundamental information on the nanoscale structure and moisture behaviour of wood. This project is a collaboration between our group and VTT Technical Research Centre of Finland, funded by the FinnCERES Flagship of the Academy of Finland. Read more on the FinnCERES webpage.

Related publications

SmartRecovery – Scattering methods for lignin analysis

This project develops methods based on the scattering of X-rays and light to study the structure of lignin particles. Our aim is to make these methods capable of characterizing structures formed by lignin efficiently and with as simple sample preparation as possible, and to yield new fundamental information on the structure of lignin particles. The project is a collaboration with VTT Technical Research Centre of Finland and funded for 2023–2024 by Business Finland. Read more about the project on the Expand Fibre webpage.

SmartRecovery logo

Past research projects

Understanding the moisture behaviour of wood in nanoscale (WooD2O)

Illustration of Wide-angle X-ray scattering (WAXS): x-ray/neutrons into wood sample in a humidity chamber plus small-angle x-ray scattering (small-angle neutron scattering)

This postdoc project funded by the Academy of Finland (2018-2021) studied how the nanoscale structure of wood responds to moisture changes and how water is involved in the hierarchical structure of wood. The location of water inside of the wood cell wall and effects caused by moisture changes were studied especially using small-angle neutron and x-ray scattering.

Related publications

Follow on  X (Twitter): #WooD2O

Comprehensive characterization of wood structure from nano- to mesoscale using small-angle neutron and X-ray scattering

Illustration and line graph showing cellulose microfibrils, a neutron beam, and a line graph of microfibrils, bundles, pores, WoosSAS dand SANS dat

This postdoc project, mainly funded by Emil Aaltonen foundation (2017-2018), developed small-angle scattering data analysis for wood samples. It resulted in the freely-available WoodSAS model, which can be used to analyse small-angle neutron and X-ray scattering (SANS, SAXS) data from wood.

Related publications


Picture of Paavo

Academy of Finland Research Fellow Paavo Penttilä

Dr. Penttilä graduated with a PhD from the University of Helsinki, Department of Physics in 2013, with a specialization in X-ray and neutron scattering. After spending in total four years as a postdoc at Kyoto University (Japan) and the Institut Laue-Langevin (France), he started as a postdoc at Aalto University in 2018. The Academy of Finland granted him Postdoctoral Researcher funding for 2018-2021, and then Research Fellow funding for 2021-2026. Dr. Penttilä holds the Title of Docent in Experimental Materials Physics, awarded by the University of Helsinki.

Picture of Patrik

Postdoctoral Researcher Patrik Ahvenainen

I studied computational and materials physics at the University of Helsinki, Department of Physics. I received my doctoral degree in 2016, focusing on studying wood and other plant materials with X-ray methods. After graduating, I received a two-year post-doctoral research grant from Kone Foundation for studying wood used in electric guitars. Before joining Aalto, I worked three years as a 3D Imaging Specialist at Planmeca where I developed algorithms for 3D reconstruction and image processing for dental and medical imaging devices. I joined Paavo Penttilä's research group in September of 2022 to continue my research on wood and other lignocellulosic materials.

Picture of Tomoko

Postdoctoral Researcher Tomoko Kuribayashi

I am a postdoctoral researcher involved in the WoodCensus project. My scientific expertise is in structural and mechanical property analysis of cellulose or lignocellulosic materials. In WoodCensus, I work on structural analysis using a transmission electron microscope and electron tomography techniques.

Picture of Aleksi

Doctoral Candidate Aleksi Zitting

I received my Master's degree in Physics from the University of Helsinki on molecular dynamics (MD) simulations of damage formation in fusion reactor materials in 2019. Starting from December 2019, I have been investigating wood-water interactions with scattering experiments and MD models, as a Doctoral Candidate concentrating on the experimental side of the SASAMIS project. The current focus of my studies is determining the nature of nanoscale structural changes due to moisture in wood cell walls using X-ray and neutron scattering.

Picture of Enriqueta

Doctoral Candidate Enriqueta Noriega Benitez

I studied space physics, including solar particle detection and simulations of such particles, at the University of Turku, where I received my Master's degree in Chemical and Physical Sciences in 2021. In February of 2022, I joined Paavo Penttilä’s research group at Aalto University in which we probe the structure of bio-based materials, chiefly wood, through the use of X-ray scattering techniques and machine learning algorithms. Currently, my work in the NNxWOOD project focusses on processing X-ray scattering data with an AI-based approach to analyze the nanostructure of wood.

Picture of Janita

Master's thesis worker Janita Makkonen

I study materials science in Aalto University, majoring in Functional Materials. Previously, I studied chemical engineering and environmental technology in LUT University, where I received my Bachelor´s degree. I joined the Biobased Materials Structure group in January 2024 as Master’s thesis worker, and I am currently working in the SmartRecovery project, concentrating on lignin characterization with different light scattering techniques.

Group picture
Group photo, team development day 2022

How to join us?

Highly motivated MSc, doctoral or postdoctoral students interested in joining the group can contact Dr. Paavo Penttilä ([email protected]).


Illustration with three line graphs and SAXS/WAXS from wood, nanocellulose, colloidal particles, soft matter nanoassemblies etc.

Dr. Penttilä teaches the course “X-ray scattering methods for structural analysis of bio-based materials”, organised next time in April/May 2024. The target of the course is to introduce doctoral and advanced Master’s students to X-ray-based structural characterization methods (both in theory and in practice) and initiate the application of these methods in the students’ own research.


Our group has ongoing collaborations with researchers from Aalto University (Finland), VTT Technical Research Centre of Finland (Finland), University of Helsinki (Finland), Institut Laue‒Langevin (France), Kyoto University (Japan) and MAX IV Laboratory (Sweden).

Latest publications

More information on our research in the Aalto research portal.
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