GuestMay 21, 2024 AATCC Newsletter

A sample of pink cotton fabric that’s been treated with nanodiamonds (left) next to untreated cotton (right). A petri dish of detonated nanodiamond powder is next to the fabrics.
Image credit: Cherry Cai, RMIT University

 

As Shiv Raja, an environmental scientist, conducts her conservation experiments at the  national zoo in tropical Kuala Lumpur, Malaysia, she quickly opens an umbrella to protect herself from occupational heat radiation. The temperature is hovering around 39 C (102 F), the range that’s going to be the normal temperature these days in most countries. And Raja’s not alone in her crusade against the spoils of the sun. If nothing is done about it, continuous exposure to excessive sun rays and heat caused by the chaotic climate will have an equally chaotic effect on us mortals.

 

In fact, there is extensive research which already states excessive direct exposure to solar radiation has a strong causal effect on skin aging, excessive heat absorption and reddening of the skin, and even to a certain extent skin cancer. This is all due to the presence of ultraviolet (UV) rays.

 

In simple terms, as Arunraaj Natarajan at Sardar Vallabhbhai Patel International School of Textiles and Management in India explains it, the hotter weather “impacts both the physical and physiological well-being of individuals from substantial strain to the cardiovascular system, to elevating the likelihood of hypertension, to myocardial infarction and related cardiovascular pathologies, and cognitive debilitation—all a strain on mental well-being.”

 

Quite naturally and obviously, one pragmatic general approach in preventing high-intensity solar radiation has been protective clothing. One strategy to create protective clothing includes modified textiles via chemical additives that have the embedded feature in providing smart cool comfort, yet protection from adverse solar climatic effects. Natarajan calls it, “strategies for encompassing optimal ventilation and hydration regimens.”

A petri dish of detonated nanodiamond powder. Image Credit: Cherry Cai, RMIT University

Why use chemical additives to enable cool protection? Ordinary natural fabrics like cotton, silk, or wool do not absorb ultraviolet radiation expediently, according to lead researcher Amal Ray from Lovely Professional University in India. In fact, research states the minimum ultraviolet protection factor (UPF) needed to safeguard from the elements of heat and radiation should be  UPF-15 or equivalent, as found by researchers Mohammad Ghane and Ehsan Ghorbani.

 

While research in terms of cool protectives is only at the nascent stage at this point, there has been significant effort and strides in terms of innovative ideas. Natarajan says, “while some may construe it as marketing hyperbole, it actually embodies a genuine solution to address multifarious requisites across diverse spheres.”

 

 

One such quick cooling idea stems from the low-cost production nanodiamond technology, developed by co-researchers at the Centre for Materials Innovation and Future Fashion at the Royal Melbourne Institute of Technology (RMIT University) in Australia. They use a technique called electrospinning. This technology can be used on cotton material, a material which most consumers use. Natarajan concurs, “nanodiamonds present distinctive attributes rendering them remarkable candidates for tackling diverse challenges, encompassing those pertinent to intelligent, cooling, and protective apparel.”

Pink cotton fabric treated with nanodiamonds (left) next to untreated cotton (right). Image Credit: Cherry Cai, RMIT University

How is cooling achieved by nanodiamonds, which are miniscule particles from diamond’s cheaper twin? As project lead and RMIT senior lecturer, Shadi Houshyar says, “easily and cheaply.”

 

“Actually, the most common method is via detonation. There are other methods employed too such as high-pressure high temperature, milling, and chemical vapor deposition,” she says.

 

Why in particular nanodiamonds? “… because of their carbon structure and high thermal conductivity property they are usually used to improve thermal properties of liquids and gels,” says Houshyar.

 

“In this case, the nanodiamonds are deliberately applied to one side of the fabric. This is to restrict heat in the atmosphere from transferring back to the body. The side of the fabric with the nanodiamond coating is what touches the skin. The nanodiamonds then transfer heat from the body into the air at a higher rate as compared to pristine cotton,” she elaborates.

 

The researchers found a reduction of about 2-3C during the cooling down process as compared to untreated cotton. Not only is nanodiamond technology able to cool cotton fabric temperatures, but also it enhanced the UV protection of cotton, making it ideal for people like Raja.

 

To many, a reduction of 2-3 degrees Celsius may not sound like much. But truth be told, as explained by Houshyar, “practically, it does make quite a difference in terms of individual comfort and health impacts over long time periods.”

 

She cites the everyday option between switching your air conditioner or not. She adds the use of nanodiamond infused fabric in clothing, which results in passive cooling, is projected to be a 20-30% energy saving due to lower use of air conditioning.

 

Beyond its prettiness and brilliance, Olga Shenderova, in her paper, indicates nanodiamonds have the combination of unique bulk and surface properties making them extremely versatile materials with a number of applications. “The outstanding chemical and mechanical properties, along with their small size and approximate spherical shape,” renders this jewel ideal, she explains.

 

From left to right: Research supervisor and RMIT Senior lecturer Xin Wang, Lead researcher and RMIT research assistant Aisha Rehman and Project leader and RMIT Senior Lecturer Shadi Houshyar. Rehman is holding pink cotton that’s been treated with nanodiamonds.
Image Credit: Cherry Cai, RMIT University

Certainly, there will be huge possibilities to gain from this technology and using it to innovate other new textiles for use perhaps as personal protective clothing, and even sportswear, protective gear, and medical apparel—as concurred by both Houshyar and Natarajan. But Houshyar expounds further by citing that these tiny diamonds can be included as underlayers to keep fire fighters or military personnel cool in extreme heat conditions.

 

The best is yet to come! As nanodiamonds are also biocompatible and non-toxic, it’s safe for the human body. So, the next target is “the bio-medical sciences sector,” exclaims Houshyar. She also shares the notion that nanodiamond technology may be used to protect buildings from overheating, which can lead to environmental benefits. Something Raja will obviously be happy to hear when she makes her next rounds at the zoo in the not-so-distant future—without her umbrella.

 

 

 

 

About the Author

Thanaseelen Rajasakran is an Assistant Professor at a Malaysian university, Universiti Tunku Abdul Rahman. He is passionate about all things concerning United Nations sustainable development goals.

 

 

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