Note: This is the third article of a three-part series covering plastics in electrical and electronic (E/E) device (1) trends, (2) material/process advances and (3) applications.
The road ahead for plastics has the potential to significantly impact future electronic device applications. In commercial applications, polymer development is pushing plastic properties in response to ongoing demand for smaller electronic devices that call for smaller, thinner electrical components in hotter environments at higher electrical frequencies.
We're seeing high flow grades that permit more intricate, miniaturized parts in electronic applications. Part cost reduction and faster production cycle times is increasingly the new norm. Polymer-based technology is being developed for the nanophotonics market that could make computers and the Internet 100 times faster.
Let's take a look at some emerging plastics in electronic device applications.
First, a new generation of batteries in automotive body panels for energy storage purposes is taking shape. Volvo has developed lightweight structural energy storage components as an innovative solution to heavy bulky battery packs. The work is being done with a consortium funded by the European Union that includes Imperial College London as the academic lead partner.
The storage components are composed of carbon fiber and unsaturated polyester resin that create an advanced nanomaterial and structural supercapacitors. The carbon fiber/polymer composite material can store and discharge large amounts of electric energy much quicker than conventional batteries.
The recharging process causes little degradation in the composite material whereas conventional batteries degrade over time. The material is extremely strong, lightweight and can be shaped for use in car body panels. The part weight can be reduced by roughly 15 percent when used to replace steel panels.
The reinforced carbon fiber-battery sandwich is molded and formed to fit around the car's frame such as door panels, trunk lid and wheel well. Volvo is evaluating the technology in the Volvo S80 experimental car. The two components being evaluated are:
- Trunk lid: where the trunk lid is a functioning electrically powered storage component and has the potential to replace the standard batteries seen in today's cars. It is lighter than a standard trunk lid, saving on both volume and weight.
- Plenum cover: where the new plenum demonstrates that it can also replace both the rally bar, a strong structural piece that stabilizes the car in the front, and the start-stop battery.
Another material, Nano Adaptive Hybrid Fabric (sometimes referred to as fuzzy fiber composites) is under development by the University of Dayton Research Institute (UDRI) and its collaborators.
UDRI presented its results for 60-inch Nano Adaptive Hybrid Fabric (NAHF-X) at their Nanotechnology Materials and Devices Workshop held in February. The material holds promise as a game-changing carbon nanotube textile that will allow conductive plastic composites to multitask, for example as vehicle structural components that also acts as a battery or a sensor system.
Continuing forward, an award-winning LED lamp bulb has entered the marketplace. The Energy Star-certified Switch Infinia recently earned the 2013 "Lighting for Tomorrow Award for Best LED Bulb."
While LED products are currently available to consumers, the lighting market has a strong need for LED light bulbs that have the same appearance and light output as the bulbs they are replacing. Switch Lighting Co is using a high-diffusion Lexan LUX PC (polycarbonate) from SABIC Innovative Plastics to manufacture what is said to be one of the lowest-cost residential LED bulbs on the market. It retails as low as $11.99.
The Lexan material with Max Diffusion technology used for the globe of the Infinia optimizes diffusion by eliminating hotspot and dark areas at the top of the globe. In addition, by using injection-blow moldable material, Switch was able to make a bulb with omnidirectional evenly dispersed light, which mimics the light distribution of incandescent bulbs.
The excellent heat-aging performance of Lexan LUX PC resins also help achieve improved lighting efficiency, while also maintaining excellent optics, light transmission and color stability over time. Heat-aging lab performance data shows that these resins retain their long-term color stability and light transmission properties, when exposed to high temperatures over a long period of time.
Elsewhere, Bayer MaterialScience has developed special polycarbonate and polyurethane materials for LED lamps. These are widely used in lens systems, optical guides, reflectors, light diffusers, cooling elements and housing parts.
In such optical components, Bayer plastics are able to guide, bundle, diffuse and reflect the LED light. Bayer's Makrolon LED product family has been developed specifically for LED applications. Their polycarbonate materials are highly transparent and conduct white LED light without significant losses. They offer plenty of freedom in part design, are lightweight and can be economically manufactured by injection molding.
Finally, the field of miniaturized electronics work continues to grow rapidly in creating a functional 3-D printed ear. Researchers at Princeton University are integrating silver nanoparticles and biopolymer-laced tissue to create a functional ear using off-the-shelf 3-D printing equipment, followed by cell culture.
The primary purpose of the work was to explore an efficient and versatile method of merging electronics with tissue. The technique allowed the researchers to combine the antenna electronics with tissue within the highly complex topology of a human ear. The researchers used an ordinary 3-D printer to combine a matrix of hydrogel and calf cells with silver nanoparticles that form an antenna. The calf cells later developed into cartilage.
In general, there are mechanical and thermal challenges with interfacing electronic materials with biological materials. Using the approach to build and grow the biology up with the electronics synergistically and in a 3-D interwoven format overcomes these difficulties.
The finished ear consists of a coiled antenna inside a cartilage structure. Two wires lead from the base of the ear and wind around a helical "cochlea." In the Princeton synthetic ear, electrical signals could be connected to a patient's nerve endings, similar to a hearing aid. The current system receives radio waves, but there are plans to integrate other materials, such as pressure-sensitive electronic sensors to enable the ear to register acoustic sounds.
This is the first time that researchers have demonstrated that 3-D printing is an effective strategy for interweaving tissue with electronics. Funding has been provided by the Defense Advanced Research Projects Agency (DARPA), the Air Force Office of Scientific Research, National Institute of Health (NIH), and the Grand Challenges Program at Princeton University.
