Developing Fully Bio-based and Colored Textile Products with Algae-Based CoatingsThe textile industry, a major contributor to environmental pollution, has long relied on synthetic dyes that pose significant ecological and health risks. The process of dyeing textiles with synthetic chemicals results in substantial water pollution, the release of toxic substances, and the accumulation of microplastics in aquatic ecosystems. Moreover, the disposal of dyeing wastewater has been a persistent challenge, causing long-lasting environmental degradation. The rising demand for sustainable, biodegradable, and non-toxic alternatives has prompted the exploration of bio-based materials for fabric dyeing.
Among these alternatives, algae-based pigments present an innovative and highly sustainable solution. Algae, a group of aquatic organisms capable of photosynthesis, offer a rich source of natural pigments that can be utilized to color textiles. This bio-based dyeing method not only reduces environmental harm but also aligns with the growing movement towards circular and sustainable industries. Harnessing algae for textile dyeing could revolutionize the industry, providing vibrant colors while adhering to environmental stewardship principles.
Fig 1. IR spectra of untreated cotton fabric (black) and cotton fabric after alginate application (red). (Blanckart L., et al., 2025)Algae are classified into several categories, including macroalgae (seaweeds) and microalgae (unicellular algae). Both types produce pigments like chlorophylls, carotenoids, and phycobiliproteins, which can be harnessed for dyeing purposes. These pigments are not only biodegradable but also exhibit a range of colors, from greens to reds, blues, and yellows, making them suitable for various textile applications.
The most notable pigments derived from algae include:
These pigments are bio-sourced and offer a non-toxic alternative to the synthetic dyes traditionally used in textile manufacturing. Unlike synthetic dyes, which often contain harmful chemicals such as heavy metals, algae pigments are naturally occurring and pose little risk to the environment or human health.
The application of algae as a coating for textiles involves the integration of algae pigments with natural binders to create a functional coating that adheres to fabric fibers. In recent studies, algae powders have been mixed with sodium alginate, a natural binder derived from seaweed, to form a paste that can be applied to fabrics. This binder helps the algae pigments adhere to the fibers, ensuring a durable and long-lasting color.
Binding and Crosslinking Mechanisms
To enhance the durability of algae-based coatings, a crosslinking agent such as calcium chloride (CaCl2) is often used. Calcium ions form stable bonds with the carboxyl groups in alginate, creating a network that strengthens the bond between the dye and the fabric. The presence of calcium dichloride improves the mechanical properties of the coating, such as its resistance to abrasion, while also enhancing the overall fastness of the dye.
The crosslinking process plays a vital role in ensuring that the algae pigments remain intact and resistant to environmental factors such as washing and sunlight. This approach mimics the chemical stability of synthetic dyes but without the associated environmental risks.
Fastness to Light and Rubbing
One of the most critical factors in evaluating the performance of algae-based textile coatings is their fastness to light and rubbing. The durability of the coating under exposure to environmental stressors is essential for determining the suitability of algae pigments for commercial use.
Light Fastness: Algae-based coatings, particularly those containing blue-green algae and unicellular algae, demonstrated reasonable resistance to light exposure. However, the pigments did exhibit some fading after prolonged exposure to sunlight, particularly those with a higher concentration of organic components. This phenomenon, known as photodegradation, is common in natural dyes, where the chromophores (color molecules) are susceptible to UV radiation.
Rubbing Fastness: The rubbing fastness of algae-coated fabrics was found to vary depending on the algae species used. Filamentous algae coatings showed superior rubbing fastness, likely due to the fibrous structure of the algae, which provides better adhesion to the fabric fibers. In contrast, unicellular algae coatings exhibited lower resistance to rubbing. The addition of calcium chloride improved the rubbing fastness across all algae coatings, as it helped strengthen the bond between the dye and the fabric.
Color Stability and Fading
Color stability is another crucial consideration when using algae pigments in textile applications. The pigments derived from algae are generally more susceptible to fading under UV exposure compared to synthetic dyes. However, the incorporation of crosslinkers, such as calcium chloride, has been shown to improve the stability of algae pigments, reducing color fading over time. This enhanced stability makes algae pigments a more viable option for textiles that will be exposed to light and frequent use.
Textural Properties of Algae-Coated Fabrics
The application of algae-based coatings also influences the texture of the fabric. SEM (scanning electron microscopy) imaging has shown that algae coatings form a thin, uniform layer over the fabric's surface. This layer fills the spaces between the fibers, leading to a smoother and more even texture compared to untreated fabrics. The coating's thickness and consistency vary depending on the algae species used. Filamentous algae, for example, can create a more textured surface due to their fibrous nature, while unicellular algae create a smoother, more homogenous coating.
Despite the promising potential of algae-based textiles, there are several challenges that need to be addressed before algae pigments can be widely adopted in the textile industry. The primary challenge is the light fastness of algae pigments, which tends to degrade under UV exposure. While the addition of calcium chloride improves pigment stability, further research is needed to optimize the formulation of algae coatings to ensure better resistance to light and other environmental factors.
Additionally, the scalability of algae cultivation for large-scale textile production must be assessed. While algae are highly productive, growing them in sufficient quantities to meet the demands of the global textile industry requires further development of cultivation techniques and infrastructure.
Another area of research is the development of alternative crosslinkers and binders that can enhance the durability of algae-based coatings without compromising their environmental benefits. Investigating different algae species and exploring hybrid coatings that combine algae with other natural materials may offer a solution to some of the current limitations.
Algae-based pigments represent a groundbreaking advancement in sustainable textile dyeing. By utilizing natural, biodegradable pigments derived from algae, the textile industry can significantly reduce its environmental impact while creating vibrant, eco-friendly products. Although challenges remain in terms of light fastness and scalability, the potential benefits of algae-based textiles are immense. With continued research and development, algae could become a key player in the future of the textile industry, providing a sustainable and non-toxic alternative to synthetic dyes.
As the world moves towards more sustainable production practices, algae-based dyeing offers a solution that aligns with both environmental goals and the growing demand for eco-friendly textiles. The future of textile dyeing lies in harnessing the power of algae—nature's own colorants—leading to a cleaner, greener textile industry.
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Reference
This article is for research use only and cannot be used for any clinical purposes.
