Jan 05 2021

3D Printed Smartgel

If you follow science and technology news closely over years certain patterns emerge. First, most advances are incremental. True “breakthroughs” are rare, despite how overused that word is in reporting. At best there are milestones – an incremental advance that reaches a critical level that will likely change the application of a technology. Second, most advances do not pan out. They add to our total knowledge, helping us inch forward, but most technological developments will not be ultimately utilized themselves. This leads to a third conclusion: it is very difficult to predict which technologies will flourish and which will be dead-ends.

All this makes science communication tricky, if you’re interested in doing it right. It’s easy just to hype potential advances and applications without context, but context is mostly what science communicators should be communicating.

With all that in mind, a couple of recent science news items caught my eye as having the potential for exciting future applications, but with all the above caveats applying. The first relates to 3D printing, which is a technology that is clearly being widely used and has tremendous potential, but it’s difficult to predict how widespread it will become. That is another difficulty in prediction – even if a technology works and is useful, we don’t know how it will be adopted. It may have a narrow niche application, or may change the world, and predictions err in both directions. But the story of 3D printing is not over yet, and it remains to be seen how much additive manufacturing will displace traditional manufacturing.

The new advance is the development of a 3D printable smartgel. This is a hydrogel that can alter its shape in response to light and temperature. A hydrogel is a solid that contains water, like jello or modern contact lenses. This is definitely a material that panned out and has many applications. The smartgels are smart because they can change their form. OK – so what? That is the big question – can this property be exploited for a usable purpose? This is the “killer app” question for any new technology. Even if it works, what application will justify high demand? Sometimes technology is developed to fill a very specific purpose. At other times technology is developed because it can be, and then goes in search of a purpose. This is definitely a form of the latter, and this is also where the wild speculation comes in.

One of the potential uses being discussed is in soft muscle for robots. This is a technological need looking to be filled. Soft robots with some form of artificial muscle will be more adaptable to more situations, may be more energy efficient, and could have greater finesse of movement, even to the point of fully mimicking human movement. And of course, this would be perfect for robotic prosthetics to replace human limbs. For this reason any technological development involving soft stuff that moves will be offered as a potential artificial muscle for soft robots, and this is no exception.

The study authors themselves offer:

“This fast, high resolution, and scalable 3D printing method for stimuli-responsive hydrogels may enable many new applications in diverse areas, including flexible sensors and actuators, bio-medical devices, and tissue engineering.”

A robotic muscle would be an “actuator”. I also need to point out that smartgels have been around for several decades, the real advance here is the 3D printing part. That highlights another pattern in science and technology news – advances often take 20-30 years before they make it to the clinic or the market (depending on how basic vs applied they are).  Advanced medical treatments coming online right now I heard about first in the 1990s.

In theory, depending on the specific properties of the smartgel, you could have an actuator (a soft muscle) that contracts when exposed to certain frequencies of light and then relaxes when the light is removed or a different frequency is applied. Of course there are many critical questions that can make or break specific applications – how strong with the contraction be, how fast will it be, will it be able to hold the shape indefinitely, and what is the longevity of the gel itself? This may be useful for applications that need only weak and slow actuators, but be entirely useless for human-scale robots. For these reasons it is possible that this specific technology will never go beyond a lab curiosity, or perhaps very niche applications. Or – if all the parameters can be worked out, it could revolutionize robotics and prosthetics, and find novel applications we are not even thinking of now. It will probably be toward the former end of the spectrum, but we’ll see.

The other news item that caught my eye (and is tangentially related) is development of an efficient and long-lived pure blue OLED (organic light emitting diode). I am presenting this mainly for the contrast. This technological development is filling an existing hole – a application looking for a technology. OLEDs are currently the state of the art for things like televisions and computer monitors. They produce amazing high quality images with high dynamic range. However, they are still pricey, compared to the older LED technology.

One main reason for this is the blue OLED, which is still an imperfect technology. There is always a trade off between efficiency, lifespan, brightness, and expense (because of the need for expensive metals). The red and green OLEDs, meanwhile, have several options with the entire suite of desirable properties. Now, however, a lab has published that they have developed a blue OLED that is closer to having all the desirable properties – long-lived brightness, no expensive metals, and energy efficient. This is a development with an existing application and the entire point of the advance is the desirable properties that will make the technology useful.

But – the tech is not quite there yet:

Adopting a tandem structure that basically stacks two devices on top of each other to effectively double the emission for the same electrical current, lifetime was nearly doubled at high brightness, and the researchers estimated that devices could maintain 50% of their brightness for over 10,000 hours at more moderate intensities.

“Though this is still too short for practical applications, stricter control of fabrication conditions often leads to even longer lifetimes, so these initial results point to a very promising future for this approach to finally obtain an efficient and stable pure-blue OLED,” says Adachi.

So again, we cannot predict if this will be the specific pathway to an advance that actually gets widely adopted. It’s closer, but has not achieved the threshold necessary for “practical applications”. For context, current OLED displays have a lifespan of about 100,000 hours, 10 times more that this technology.

These are incremental advances that may or may not go anywhere, but they highlight the state of their respective technologies and the challenges we have before us. Also, even if these specific technologies do not pan out, others likely will. In the aggregate robotic technology and display technology advance. We will have soft robots, one way or another. We will have brighter cheaper displays, even if this is not the specific technology used. That is the final pattern I have noticed – you cannot predict the details, but often the bigger picture is fairly predictable.


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