By Ella Copeland...
Recently Construction Digital looked into the emerging possibilities offered by biomimicry, focusing on architects who are taking inspiration from nature’s processes in order to create sustainable solutions to climate change. In a new move, Scientists are taking this concept one step further, creating materials which mimic a living substance.
Even the most basic of living organisms have developed sophisticated ways to sustain a continual state in a changing environment. Be it maintaining an internal temperature, pressure, or pH, living organisms are able to self-regulate, inspiring scientists to attempt to transfer this ability to buildings.
A team of engineers led by Harvard University have developed a material called SMARTS, (Self-regulated Mechano-chemical Adaptively Reconfigurable Tunable System), an ‘intelligent material’, which is able to maintain a constant temperature. This newly developed platform is customisable, able to autonomously regulate its temperature, pressure or pH through ‘dynamic self-powered feedback loops’ which produce a chemical reaction that can be turned on and off.
SMARTS resembles a microscopic toothbrush, with bristles that can stand up or lie down to increase or reduce the temperature. It operates in a similar way to hair on human skin, which stands up when we get goosebumps.
“When it iscold out, tiny muscles at the base of each hair on your arm cause the hairs to stand up in an insulating layer. As your skin warms up, the musclescontract and the hairs lie back down to keep you from overheating. SMARTS works in a similar way,” explained lead author Joanna Aizenberg, the Amy Smith Berylson Professor of Materials Science at the Harvard School of Engineering and Applied Sciences (SEAS).
Ximin He, postdoctoral fellow and co-author of the report, hopes that this technology could be applied to the windows of buildings to keep heat inside: “One area we’re very interested in is using them as bottom-up architectural materials for self-regulated, energy-efficient buildings. For example, since they’re thin and can be made transparent, they can be used to coat windows, usually the most vulnerable parts of a building temperature-wise.”
In the experiment conducted last month, Ximin and her team produced evidence that SMARTS can actually ‘warm up’ a building: “The thermally self-regulating SMARTS that we have demonstrated can maintain their local temperatures. Whatever the system for warming a building up, it only has a capacity that is dictated by the heat evolution capacity of the ‘fuel’ used. The chemical reactions we use do possess substantial heat releasing capacity and we are working on figuring up how much it can be scaled up.”
SMARTS are self-powering materials, which use chemical reagents as the ‘fuel’ to continuously adjust and sustain the self-regulation of the local conditions, particularly temperature, which was proven in the recent demonstration. According to Ximin, the materials are inexpensive and easy to mass produce, yet there are still areas of the product which require more research:
“SMARTS are believed to be a promising sustainable way of maintaining the local temperature and can be developed for the applications in energy-efficient buildings. There are two limitations, however: at present, the system relies on horizontal stratification, which means that we are talking about horizontal windows, like skylights, etc.; another fundamental question has to do with the scaling the system up, since it is diffusion controlled, which puts constraints on the response times as a function of the gel size.”
The main advantage of SMARTS is that they are self-powering materials, which don’t often need replenishment. They use chemical reagents as the ‘fuel’ to continuously adjust and sustain the self-regulating of the local conditions, particularly temperature. In addition to this, the materials also have a long shelf life: “If they are not actively being used, the basic materials that SMARTS are composed of are stable in ambient to last for years. If they are actively being used, considering the ‘fuel’ chemical reagents are consumable, one needs a replenishing system that automatically replaces the chemical reagents continuously as needed. The lifetime of the material is determined mainly by the hydrogel and structural components, which are expected to last for years.”
The team hopes that SMARTS technology could be made available for common use in the next few years as an environmentally friendly heat retaining solution: “SMARTS is made of easily processed synthetic materials, for instance in our demonstration, hydrogel and nano/microstructured epoxy, are both made in one step by shining light for a few to tens of minutes. As highly-customizable and tunable materials, they can also be made of broad options of other synthetic materials. Therefore, it is facile and non-costly to make fairly large-scale SMARTS-containing elements.”