Stretch fabric

Company background

Davy J is a new British swimwear brand that creates beautiful active swimwear, all manufactured in the UK and made using ECONYL® yarn, a nylon yarn regenerated from 100% marine waste materials. As a brand Davy J creates swimwear that is designed to ‘survive a dive’, fighting the trend of throwaway fashion and creating something that can be used in all conditions. A double lined, high elastane composition provides extra strength, durability and shape; with hidden rubber edging and cross back designs the styles are built to ensure you surface from the water in the same condition as you entered it.
Davy J are a circular brand and have an end of life returns scheme for all their swimsuits so that wherever possible the resources within them can be recycled. The company's aim is to work towards a closed loop recycling system so materials can be regenerated at end of life. 
DavyJ swimsuit

What did they want?

Davy J wanted to analyse the differences between their fabric and a competitor's fabric. This would include a visual analysis of the weave, particularly looking for any visual differences between the nylon and elastane threads, how the fabrics acted after being submerged in seawater and air-dried, along with how the fabric looked during stretching.

Agreed analysis plan

It was agreed that all fabrics will be analysed using simple scanning electron microscopy (SEM) at various magnifications to compare fabric weave under the different conditions. To analyse the effect of not washing salt-water wet fabrics, the fabrics were submerged in salt water for 30 minutes and left to dry naturally over seven days. To observe how the fabrics appeared when stretched, each fabric was stretched in the parallel and subsequently perpendicular to the weave direction (separate samples for each fabric were stretched).

Visual analysis

Initial results showed that the Davy J's fabric, regardless of colour, visually looked the same and had the same weave. The same can be said about the two competitor fabrics, as they visually looked the same and had the same weave. However, the two weaves were different which is shown here to the right. With the left micrograph showing the weave of a Davy J product and the right showing the weave of a competitor product.
Comparison of swimsuit fabrics
Stretched fabric comparison

Stretch analysis

For each of the supplied fabrics, two samples were analysed so as to analyse stretching both parallel and perpendicular to the weave direction. A noticeable difference between Davy J's fabrics and the competitor fabrics were observed, which can be seen here to the left. The upper left micrograph shows a Davy J fabric stretched parallel to the weave, the upper right micrograph shows the a Davy J fabric stretched perpendicularly to the weave, the bottom left micrograph shows a competitor fabric stretched parallel and bottom right micrograph shows a competitor fabric stretched perpendicularly to the weave.
It was observed that the weave for the Davy J fabrics appeared tighter compared to the competitor fabrics, which appeared looser and showed more gaps. It was also observed that the Davy J fabrics had a secondary weave which is only apparent in the stretched micrographs.

Seawater analysis

Once the fabrics were fully dried in air they were analysed to study the condition of the fabrics, which can be seen here on the right. The left micrograph shows a salt deposit on a Davy J fabric and the right micrograph shows a salt deposit on a competitor fabric.
It was observed that the Davy J fabrics had little-to-no salt deposits on or in between fibres, which showed that they would still perform well even if they weren't washed after use in seawater. However, salt deposits were clearly visible on and in between fibres of the competitor fabric.
Salt water fabric comparison

Company feedback

“This study gave us a new insight into the micro properties of our fabrics and their performance characteristics. As a growing South West business, access to such technology on our doorstep with the University is invaluable.”
Helen Newcombe, Davy J founder