How cellulose nanocrystals enable wet spinning of smart textiles

Smart textiles are designed to integrate advanced technologies or materials to provide enhanced functionality and versatility, adjusting their properties in response to environmental conditions or user needs.

These textiles offer numerous advantages, such as improved comfort, enhanced athletic performance, and greater safety.

Textile fibres can be transformed into smart fabrics with thermoregulating properties by the incorporation of a phase change material (PCM). Among other methods, PCMs can be incorporated into textiles via microencapsulation – tiny PCM particles are enclosed in polymer shells and embedded into the fibres of the fabric.

PCMs change phase (from solid to liquid and vice versa) in response to temperature changes, absorbing heat when melting, and releasing heat when solidifying.

Textiles containing phase change materials can react rapidly to changes in environmental or body temperatures, retaining or releasing heat based on the surrounding temperature. By changing phase, PCMs stabilize the temperature within a narrow range, providing thermoregulation and improving wearer comfort, health, and safety.

Eco-friendly smart textile fibres for a sustainable future

Thermoregulating smart textiles are an exciting area of innovation, but they currently face several obstacles that limit their development and adoption. Petroleum-based synthetic textiles such as nylon or polyester, which are often used to make smart fabrics, are not eco-friendly:

• Their production depletes non-renewable resources and is not sustainable
• They are non-biodegradable and create persistent environmental pollution at the end of the product life cycle (disposal)
• Microplastics can be released during wearing and laundering, posing risks to aquatic life and ecosystems

Switching to sustainable bio-based and biodegradable fibres for smart textile production is a priority to decrease reliance on petrochemical feedstocks, reduce waste, and protect the environment.

Cellulosic fibres, including those derived from wood, are naturally occurring eco-friendly substitutes for synthetic fibres. Fibres spun from water-based dispersions of cellulose nanofibrils (CNFs) not only take advantage of the outstanding properties of nanocellulose, but they also require no solvents and only mild coagulation media. Adding PCMs will further broaden the use of these cellulose-based man-made fibres.

Alongside their many benefits, cellulosic fibres alternatives face some inherent technical difficulties: Many thermoregulating textiles rely on PCMs such as paraffin wax for heat storage and release. However, these nonpolar waxes are not compatible with the water or the polar natural fibres, preventing their incorporation into cellulose-based textile matrices.