Researchers cut disordered lattices from liquid crystal elastomer, a stretchy polymer embedded with liquid crystal units that can shift orientation. Compressing the lattice trains it to remember that shape, so an untrained lattice bulges outward when pressed but a trained one contracts inward on both axes, an auxetic response. Because the material can be reheated back to its original form, the same lattice can be retrained repeatedly for different mechanical behaviors, which the hosts compare to how pluripotent stem cells can be directed into different cell types.
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The hosts note the paper's own term 'pluripotent' functionality as a direct analogy to pluripotent stem cells changing fate based on transcription factors and environment.
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The lattice is described as a network of struts and nodes made from poly-domain liquid crystal regions, similar in principle to the liquid crystals used in LCD displays.
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The hosts frame the appeal for engineering as materials whose mechanical response can be customized after fabrication, with potential use in soft robotic components.
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1:58:55final paper 2025. This is a training and retraining liquid crystal elastimer metamaterials for pur potent functionality. That word pur potent I've only seen in the context of plur potent stem cells same right and so now I'm seeing it in metamaterials and I was obviously pee I was like what what exactly are we talking about so this is a paper >> about disordered lises cut from liquid crystal elastors and elastor is like a rubber-l like polymer okay so it's like it has some kind of deformability in some sense um the liquid crystal component is because you've got all of these little um crystal subunits that
1:59:40can be kind of liquid in that they can move around and that's how we get LCDs like LCD displays, liquid crystal displays. That's because you have these pneumatic liquid crystals that can like change orientation based on some type of electric field that will let through light and block light. That's how we get like the calculator LCD displays. So, it's it's a it's a crystalall-like nature that is not rigid but can sort of move around. That's why it's liquid in some sense. Um, so the network is a sheet of these connected struts and nodes and the researchers make a flexible irregular lattice and they hold it compressed so it adapts to this compressed >> environment and then they test whether it bends different differently afterwards. So there's a memory here and
2:00:22that's where the pur potent part comes in. >> Okay. >> Okay. because you can change how the material is going to behave based on the stresses and the environment that you put it through. Very similar to how in plur potent stem cells. >> Yes, >> you can change what the stem cells become based on the types of transcription factors and the environment and the genetics that you expose these stem cells. The same stem cell could go on and become a bone marrow or a skin cell or a blood cell so on and so forth based on the types of genetic factors that you put it. >> We're giving it multiple uh multifunctionality based on environmental factors which obviously
2:01:03has it makes it a lot you could do more. >> Exactly. Yeah. So let's look at figure number one. Okay. This is what the lattice is made out of. um the blue elongated shapes there, there's reg they're regularly aligned liquid crystal units within some kind of stretchy polymer. Okay, poly domain means different little regions that have different orientations to begin with. That's again akin to like the liquid crystal displays that we were talking about. And this is again in pen. The chemical structures on the right show how the researchers could make these cross- linked elastors. So they can like actually interact with one another but not be so rigid that they can't move around. >> Okay. >> And on the right hand side we're
2:01:44actually seeing how this elastimemer interacts with this environment and remembers the environment that it was in. Um before training on the top row you you push down and the sides move outward. Right? And this is the usual behavior of a material under compression. On the bottom row this is after training. you put push down and the lattice actually moves inward. >> The lattice contracts in both directions. This is called an osetic response. So, it's actually a little bit different than what I just stated, which is like it retains its original construction or connections under different compressed or pressure environments versus versus becoming victim to the
2:02:26external Yeah. >> uh force that's being applied to it that then changes its its construction. >> Yeah. Yeah. Yeah. It has a memory and it can like now that you've compressed it already, it can now do the thing that you want it to do, right? It has like a memory and for an engineering op audience like the implication is very appealing because these are materials whose response can be customized >> after fabrication. So you just get it from the factory. You can enact stresses to this material and you can customize it and perhaps you can adapt it to structures or soft robotic components like the robotic component that we just saw. Um, and it demonstrates a lab route
2:03:06to retrainable mechanical function, right? Because you can take the same polymer now and reuse it. You can heat it up and it'll come back to its original shape and then you can do something else with it. You can put different stresses to it that'll make its response different >> in some sense, right?
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