New Research Shows Way to Build Effective Materials for Superior Thermal Management

We often recognize materials based on their properties. However, the advances achieved in material science and engineering have made it possible to produce materials that combine unusual properties, which are often in stark contrast with each other. 

In a recent example, a team of researchers demonstrated the possibility of engineered materials that are both stiff and capable of offering insulation properties when exposed to heat. 

According to Jun Liu, co-corresponding author of a paper on the work and an associate professor of mechanical and aerospace engineering at North Carolina State University had the following to say about the uniqueness of the discovery and the material:

“We”ve now discovered a range of materials that are both stiff and excellent thermal insulators. Moreover, we can engineer the materials as needed to control how stiff and thermally conductive they are.”

Usually, one finds that materials with high elastic modulus, a property that manifests itself through increased stiffness, are not insulating. They are, quite on the contrary, highly thermally conductive. 

But what if we need materials that would act as good insulators without losing their stiffness? These materials will come in handy in scenarios involving creating thermal insulation coatings to protect electronics from high temperatures.

Delving deeper into the material and inquiring more about the research shows that the materials the researchers worked on are a subset of the two-dimensional hybrid organic-inorganic perovskites (2D HOIP). These materials consist of thin films that consist of ‘alternating organic and inorganic layers in a highly ordered crystalline structure.’ What adds to their value is that it is possible to tune the composition of either the inorganic or organic layer. 

The process involves replacing the carbon-carbon chains in the organic layers of these materials with benzene rings. This leads to a scenario where it is possible to control or regulate the elastic modulus and thermal conductivity. 

The research helped the team to come up with at least three distinct 2D HOIP materials that became less thermally conductive the stiffer they got.

Apart from making stiff yet insulating materials, the research also helped introduce chirality into the organic layers, implying that the same stiffness and thermal conductivity could be sustained without having to make substantial changes to the composition of the organic layers. Further progress in this aspect might ensure the possibility of optimizing other characteristics of these materials without worrying about the impact of these changes on a material’s stiffness or thermal conductivity. 

When it comes to assessing the on-ground application potential of these materials, many companies can benefit from this research. These companies have the R&D resources to take this research forward, try it out on a larger scale, and integrate its benefits into their existing product line or create a new product line altogether. In the following segments, we discuss a couple of such companies and look into ways these companies can adopt this innovation. 

#1. Owens Corning

Owens Corning’s Foamular line of products comprises high-performance extruded polystyrene insulation. Extruded polystyrene foam consists of closed cells and offers improved surface roughness, higher stiffness, and reduced thermal conductivity. 

Its high-performance extruded polystyrene offers insulation through a product that is durable, versatile, and resilient and comes in handy for a range of use cases in architecture, engineering, and construction. Apart from its insulating properties, the materials are also moisture resistant. 

Owens Corning has a proprietary manufacturing process named Hydrovac that manufactures these solutions. The process offers a consistent closed-cell structure, free of voids, which keeps moisture out while delivering an R-value of 5 per inch of thickness. In the context of insulation, the R-value is a measure of how well a building’s insulation can prevent the flow of heat in and out of the home. The higher the R-value, the greater the performance of the insulation product. 

The product has compressive strengths ranging from 15 to 100 psi and is manufactured in compliance with ASTM C5781. It could be the ideal choice in Protected Roof Membrane Assemblies (PRMA) for vegetative roofs, which can withstand wet soils and loads. Additionally, it is lightweight, easy to handle, and compatible with common exterior claddings and finishes. Not only does the product offer up to 13 times more resistance to water than conventional EPS insulation, but it also retains a minimum of 90% of R-value over 20 years.

The research on hybrid organic-inorganic perovskites (2D HOIP) we discussed in the earlier segment could offer Owens Corning new avenues to augment its leadership in this space. 

Founded in 1938 and based in Toledo, Ohio, Owens Corning recorded net sales of $9.7 billion in 2023.

#2. Gore

While discussing the research on 2D HOIP, we saw that the materials had the potential to offer thermal insulation to electronic materials. Gore, a company specializing in thermal insulation for mobile devices, will benefit from these materials and the research.

Gore Thermal Insulation is an advanced thermal management solution that has conductivity lower than air. It can increase design flexibility and the designer’s ability to direct heat through greater control of z-axis thermal conductivity. Improved control of the z-axis means superior spreading options that help components perform at higher levels for longer periods, accommodate shrinking form factors, and meet surface temperature requirements. 

Apart from its sophisticated thermal insulation properties, Gore’s solution has other performance benefits, including being easy to integrate and having the backing of a team of engineers that supports design guidance and modeling integration from the early design cycle through commercialization. 

Founded by Bill and Vieve Gore in 1959 and headquartered in Newark, Delaware, United States, Gore has an annual revenue of US$4.8 billion. 

Further Research on the Dynamics Between the Nature of Materials and their Thermal Conductivity

Insulation has a wide range of application potential. Eventually, most of the spaces and materials in our everyday lives require protection from heat. It is quite natural that not all sorts of materials fit every type of application scenario. 

Research on thermal insulation performance and its impact on indoor air quality of cellulose-based thermal insulation materials investigated various factors influencing thermal conductivity. These factors included the type of raw material used, manufacturing processes, density, moisture content, and the temperature of the test environment.

The research also pointed out some correlations that would prove necessary in developing materials of superior and unique insulating properties. For instance, the research noted that moisture negatively impacted thermal performance. Conversely, an increase in density, achieved through material compression, tended to reduce thermal conductivity, particularly for materials with uniformly distributed air gaps.

The research delved deeper to list specific product compositions whose thermal performance was the best at their natural densities. One product comprised cellulose acetate, waste cigarette filters, waste cigarette paper, and waste aluminized paper. Another comprised waste papers only. 

When it came to sorption capacity, the most obvious intensification of sorption could be found in the case of the thermal insulation material made from wood fibers and the one made from cellulose that came from waste cardboard, poor processing, and inhomogeneous products. 

The research was deemed useful as it analyzed thermal insulation materials made from recycled agro-industrial waste. These materials, often present in construction materials, remained underdeveloped.

The research that sparked our current discussion aimed to protect electronic goods from heat. There are also examples of research conducted in this space. A team of researchers from Xi’an Jiaotong University, Xi’an, China, for instance, conducted an experimental study on active thermal protection for electronic devices used in deep-downhole environment exploration. In the next segment, we will go deeper into that research and its findings.

Click here to learn about the self-heating concrete that could help our roads, aquifers, and wallets.

Active Thermal Protection for Electronic Devices Used in Deep−Downhole−Environment Exploration

Let us begin with what deep-downhole-environment exploration is. It is one of the most critical application areas of electronic devices wherein devices are used to exploit and extract shale oil. The challenge arises from the fact that it is a zone of high temperature combined with high pressure. The thermal conditions in these spaces could be so severe that they could jeopardize the safe operation of electronic components. The researchers, in this case, studied an active thermal−insulation system consisting of a spiral annular cooling plate (ACP), a thermal storage container with a phase−change material (PCM), and an aerogel mat (AM). 

The team experimentally measured the impact of the ACP’s structure, layout, and working−medium flow rate on heat−protection performance. Performance implied two parameters: temperature−control capability and system−operating time. 

The research found that an aerogel mat layer was necessary and that the inner ACP case displayed better thermal protection performance. The study also proposed an annular cooling plate (ACP) with spiral flow for hybrid thermal protection with insulation material for use in deep downhole environments.

Another study, conducted in 2022 and published in the journal Nature, investigated soft, stretchable thermal protective substrates for wearable electronics. 

Soft, Stretchable Thermal Protective Substrates for Wearable Electronics

Many medical applications today are based on the effective use of wearable electronics. In that sense, these products require careful handling. However, during operations, these devices might get overheated, causing thermal discomfort or damage to the skin. A team of researchers searched for materials and structures that could provide advanced thermal protection. 

They reported a soft, stretchable thermal protective substrate featuring a composite design. It comprises the highly popular polymeric material polydimethylsiloxane with embedded heat-absorbing microspheres, consisting of phase change materials encapsulated inside the resin shell.

The results were promising as the substrate could be subjected to complex deformations over 150% and could reduce the peak skin temperature increase by 82% or higher under optimizations. 

Material Improving Steady-State System Performance in a Thermally Stressed Google Pixel 3XL

Another interesting example of selecting the appropriate thermal insulating material involved the use of graphite foils with ultra-high spreading capacity and insulation sheets with ultra-low thermal conductivity. These were deployed on modified Google Pixel 3XL to reduce surface touch (skin) temperatures.

The deployment was carried out to minimize the impact of the device junction temperature compared to standalone insulating solutions like air or graphite while also enhancing the device’s steady-state system performance. Four unique thermal solutions of comparable thickness (~350 µm) were fabricated for the experiment. Afterward, these solutions were subjected to thermal stress testing in the Pixel via 3DMark—Sling Shot Extreme.

The results were promising. The steady-state touch temperatures came down by up to 3.2°C with a <1°C increase in max junction temperature (TJ) when compared with single-component thermal solutions of graphite, insulation, and air.

The research concluded that high-performance insulation-graphite composites could offer significant utility in empowering high-powered, thin architectures of mobile electronics. However, the optimal design configuration might vary, as each mobile electronic system could present unique thermal challenges owing to its diversity of system power and available space.

Overall, heat conservation is a practice that has immense potential to help us achieve the models of sustainability we want for a greener future. Any research on effective insulation or thermal management is essentially research on materials, looking into their unique properties and optimizing them as needed. Current research trends show that enough work is already being done in that direction. The efforts will only intensify in the days to come. 

Click here to learn about the adaptive roof tiles that may be key to reducing heating and cooling energy consumption.