Footwear is a complex subject. Regular boots can have more than 50 components, making them far more intricate than most clothing items. This complexity is further heightened by the reduced scale on which these components must function. Each day, walking produces about half a liter of sweat per foot. If this moisture cannot escape, it creates ideal conditions for blisters to form.

The waterproofing debate
A major discussion in footwear revolves around waterproofing. Consumers have been sold the idea of staying dry, making waterproof components the default choice. However, is this always the best option? It's clear that not all shoes need to be waterproof, flip-flops and sandals, for instance, are designed for warm weather and don’t require waterproofing. Leather still provides the greatest solution, it is durable and offers a degree of water repellency. However, scientific advancements have introduced a new generation of materials that are now in the spotlight, especially as apparel membranes have evolved.

Modern materials and its impact
Modern synthetic yarns have revolutionized shoe uppers. These materials dry quickly, are lightweight, and require minimal maintenance (just a wash or brush down, no need for extensive cleaning and conditioning). They are also much cheaper than leather, which is why they have become so popular. However, these fabrics have no protection against wet weather, necessitating the rise of waterproof membranes.

Membrane technologies
The status quo in footwear revolves around the choice of using a membrane or not. There are several types of membranes:

• Microporous membranes: These have holes large enough to let perspiration out but small enough to prevent water from entering due to surface tension. They are the most well-known in apparel industry for their breathability.
• Hydrophilic membranes: These absorb moisture through the center of the yarn and allow it to move outward as heat and pressure build inside the shoe.
• Electrospun membranes: A type of microporous membrane with larger holes, offering more breathability but allowing water to penetrate under pressure. They are suitable for limited water exposure but are less common in branded footwear, possibly due to durability concerns.

Leather and other considerations
Leather is naturally water-repellent and breathable, though it does not perform the same as modern synthetic options. However, it is more durable and long-lasting with proper care.
AND: The durability of water-repellent treatments also plays a role. When compromised, microporous membranes can lose up to 50% of their permeability, whereas hydrophilic membranes lose around 25%.

Proper Waterproofing
It is important for waterproof shoes to make them water-repellent. Once the material gets soaked, the shoes lose their breathability. This is also true for natural materials like leather, where the pores are not sealed during tanning to maintain breathability, which means the downside of them becoming wet means water ingress as well as no permeability of perspiration. However, this means that they are not completely waterproof, which can be a disadvantage in damp and cold weather. Wet shoes that do not dry properly are also at risk of developing mold. Proper waterproof treatments can prevent this.
In addition to its protective function, the durable water repellent finish helps preserve the color of the shoes and extends their overall durability.

Footwear structure and function
A functional footbed is essential to reduce the stretching of foot bones. The mid-layer absorbs incoming pressures, while a plate helps distribute the load, reducing the impact on specific areas of the foot. Uppers protect against external conditions. Additionally, all footwear has an opening around the ankle, which can allow the wet to enter if the water is deep enough.

Conclusion: A damp foot is prone to blisters and loses heat 38 times faster than a dry foot, leading to significant issues. The ongoing challenge in footwear design is to balance breathability and waterproofing effectively.

Is there another solution? The quest for the perfect balance continues, inviting further innovation in footwear technology.

Learn more about last show´s Footwear innovations and highlights with a short sharp presentation from 4 of the best, wrapped up with one from the Sustainability Lounge & Sympatex here!