From forest to function: Lignin-based anti-fog innovation
Dr Alexander Henn, R & D manager at Boreal Bioproducts, shares insights into the development of LigNoFog
Lignin is the second most abundant organic polymer on Earth, yet its potential has often been overlooked. In trees, it acts as a natural glue, binding cellulose fibres and creating structural integrity. But once extracted, its complex heterogeneous structure presents technical barriers including irregular bonding, low solubility and inconsistent reactivity.
These challenges have meant that historically, the main use for lignin has been to burn it for energy. This even accounts for as much as 10 % of Finland’ s energy usage. Now, due to concerns over plastic usage, fossil fuel emissions and climate change, the potential of lignin is being explored again, this time with new technologies.
Demand for paper is also decreasing and, with the price of raw materials and energy rising, the paper and pulp industry is facing some real challenges. Developing high-value lignin-based products could be a game changer for this industry, allowing it to sell its‘ waste’ for profit and also contribute to a more sustainable business model.
Material science behind LigNoFog
Chemically, lignin is a randomised polyphenolic macromolecule. Unlike cellulose, which consists of repeating sugar units, lignin is believed to be formed via uncontrolled radical polymerisation of monolignols. This results in a three-dimensional aromatic network rich in phenolic hydroxyl groups and stable C-C linkages.
The biosynthesis, according to current understanding, is inherently inconsistent, meaning that no two lignin
chains are the same. This complicates application. In addition, once the lignin is extracted through thermal or chemical processes, its structure changes further, often resulting in a heterogeneous polyphenol with little order, poor solubility and limited reactivity.
Boreal Bioproducts has addressed this challenge by developing a stabilisation method that allows lignin to be dispersed in mildly alkaline water. SOLV technology uses biobased stabilisers and selective removal of the most hydrophobic fractions.
This makes it possible to create stable dispersions from pH 8 upwards, meaning SOLV is non-corrosive and safe for consumer products. This method allows us to convert low-value, abundant residues into functional materials.
Process & performance
The SOLV method begins with pressurised hot water extraction( PHWE), a chemical-free technology that uses subcritical water to isolate
Figure 1- Surface tension vs. concentration of SOLV dispersions at pH 10
lignin from sawdust under mild conditions. PHWE preserves functional groups and avoids the harsh structural degradation typical of kraft lignin.
Stabilising the extracted lignin relies on precise pH control and colloidal engineering. By avoiding strong acids or bases and working with recyclable inputs, SOLV achieves high material compatibility while maintaining environmental safety. This process supports modular integration into biorefineries, with potential for scalingup at industrial sites.
The functional target for LigNoFog is to maintain a clear optical surface under variable humidity and temperature. Anti-fog coatings function by altering surface energy, encouraging water to spread into a uniform film rather than forming droplets. This requires surfactantlike behaviour combined with optical transparency and adhesion.
Initial evaluations of the product included in-house testing on goggles during runs and swims. These tests indicated a strong anti-fog
82 SPECIALITY CHEMICALS MAGAZINE ESTABLISHED 1981