Smart Materials crazy ideas on the horizon

we're interested in smart materials which are materials which have the ability to change their shape or change their color or or change in other ways change their physical properties in response to external stimuli now the materials which we're interested in particular are materials that change their shape so they function a bit like artificial muscles hence we refer to them as artificial muscle materials and they have the ability to move or change shape in response to external stimuli such as the application of an electric current or a change in temperature or when they're placed within a strong magnetic or electrical field we use we use shape-memory alloys and in this particular project we were we we were trying to build a robotic tentacle and we've used we've use shape-memory alloys which are configured to contract when you are part you when you pass a small electric current through them in fact the electric current heats the shape memory alloy alloy up and causes it to contract due to a change in its crystal structure as it's heated so we built this robotic tentacle out of a soft material which is fabricated by 3d printing so you can see the material is is soft and bendy and we incorporate it into the structure passageways into into which we could introduce the smart materials which allow it to move so by passing an electric current through the muscle it contracts which which can create this lifelike movement you see it moves in moves in all different directions it can move through 360 degrees so it's capable of this some of this very lifelike movement and it's made out of soft materials so the idea is that it for example it could work safely within close proximity to a person whereas robots made out of hard materials can sometimes be dangerous we're exploring the idea of making robots which are safer because they're made out of soft materials well the the tentacle design which I've demonstrated here could be used in a number of different ways for example we imagine fitting a small camera a video camera onto the to the tentacle so you could create a camera which would look in lots of different directions to explore an environment for example you could use it to look inside a place like a car engine or something which was difficult to reach using or difficult to see inside you could make a camera which could look inside a hard-to-reach place or for example we could put a tactile sensor on the end of the tentacle so it could explore the in a tactile way its environment or perhaps you could have three of them which together would function as a robotic gripper the structure the the structure of the tentacle is made by 3d printing but it's not printed in a rigid material it's printed in a soft rubber like material and 3d printing means that we can quite easily make very complex shapes without having to worry about the conventional limitations of for example molding or machining with 3d printing you can make almost any imaginable shape so we've been able to form these these soft structures as a single piece including all the internal cavities which are needed to into which the artificial muscles are fitted so quite easily we can make a very complex structure also as we're aware 3d printing is increasingly affordable so it's possible to make quite a complex robotic device relatively cheaply and easily whereas in the past it it may have cost thousands of materials to make a robot such as this tentacle now we can make it for hundreds of pounds and so what we've got here is the electroactive polymer which is a membrane around the outside and that's clear a nice transparent elastic membrane and it's been stretched over this frame so this is a very simplest form of artificial muscle that we're going to demonstrate and in the middle you see a black electrode material so we have electrodes on both sides and you see the wires coming down on the right on the left here which are we going to apply some electricity to those and the ball in the middle is going to move up and down and the reason it moves up and down is because we have these electrodes on the top and on the bottom of the material when we product wristy these electrodes expand when they expand the material becomes slack it becomes loose and the ball then is free under gravity to move up now so this experiment does is to shows two things first of all it shows that the membrane can deform can show response under electrical stimulation but it also shows that we can turn the areal expansion of this membrane into something really useful which is moving a ball up and down so of course in this case the ball is is just showing movement but we could have it pressing a switch we could have it configured as a pump all sorts of other things so what I'm going to do now is just switch on the power supply to it you'll see that it moves up and down and hope you can see here I'm not going to put my hands too close because this is running at reasonably high voltage what's happening is the ball is going up and down because the membrane is expanding now later we'll take the ball off and you should be able to see the membrane expanding on its own without the ball the reasonably robust materials and it should be able to do this for quite a long time provided we don't increase the voltage too much if you have to do that when the material is going to degrade that means of course that there's some really interesting avenues for research in this area to increase their robustness to increase the number of cycles that they can run on and to make more effective machines the kind of machines that you can make and then send out into the environment without the breaking but here we have our actuator that we saw before where we've reconfigured it so that it's working as a kind of chromatophore chromatophore is a cell that's used by many organisms to change their color so for example squid and cuttlefish and octopuses will use their chromatophores to change from a white structure from a white coloration maybe into a brown or more colored appearance and also for for communication and to attract mates and all sorts of really interesting communication of course they need that for camouflage to hide themselves in their environment too so one application for these technologies is to use for artificial camouflage of course we don't just need to have camouflage which hides people or hides things we could also maybe turn these materials into some kind of wearable skin for example and in that case we could use these artificial chromatophores as a kind of display you could imagine having yourself covered in some kind of second skin where these chromatophores will be changing color over your body of your clothes and they would add a new dimension to communication and also maybe to fashion so in this simple example here we've got the member and I'm not going to touch again because this is high-voltage stuff so we've got our simple membrane in this case with high voltage being applied to these compliant electrodes and so the black material here is acting a foot two purposes the first is it's conducting the electricity into the center and conducting the electricity away afterwards as well and also because we're using this here as a chromatophore it's the color change that we want to capture so you can see here that the spot which is beating quite quite fast about four times a second or so or two times a second I think in this case what's happening is the spot is expanding and it's the the dark areas getting bigger so if we were to step a well away and we've had lots of these across them are as your skin then the coloration of the organism or in our case our clothing or second skin would change now here we've got this as a black material there's no reason why we can't have other colors - and of course we can start combining them so you can imagine that we could make some smart skin which is not just black not just changing color from white to black but also maybe changing colour using the red the green and the blue we put them all together we can have a nice color-changing artificial skin of course this isn't the only application and these membranes here can be used for all sorts of things so from pumps to artificial muscles even we can use these to create complete organisms so for example if you were to take this this kind of structure and we reconfigure it a little bit it'll be a little bit like the pumping of of a stomach peristaltic pump of the stomach well that means that we can use these organisms these artificial organisms instead of conventional robotics so instead of using motors and gears and other things which we traditionally use we'll use these instead that also means that we are not faced with the problems we have conventional technologies for example if you're going to make a motor it's got magnets it's got windings it's really quite a complicated structure that makes it more difficult to make these motors these things smaller with these materials on the other hand we can make them quite small we can even go down to or a few hundreds or even smaller of a few hundred micrometers this is really very small things almost as thin as a human hair now if we can do that facilities for these things are really quite a novel not only that because these materials are soft they're very attractive for interactions with other soft things like the human body the human body is soft and we'd like to interact with others other objects which are soft too so you can imagine taking these materials and creating devices that go on the outside of the body and interact with them but also go inside the body so now we're moving into the the ability to create implantable medical devices which are soft that's really attractive not only that but the mechanisms that we use for fabricating these can be personalised so we can end up making a structure which are geared to a particular person we can take a scan of a person MRI scan for example and then we can fabricate some soft structure using these technologies and then we can implant that into a person and treat an illness now of course we're a few years away from that and there's lots of research that's got to go into this so if I list off some of the things we've got to look at we've got to look at these new materials we've got to make them more effective more efficient to make their lifetimes longer we've also got to reduce the voltage the operating voltage of these things if you're going to implant a medical device you can't have it running at their high voltages that we've got here the kind of thing you can't touch it's got to be at a safe voltage so there's lots of interesting research not into that we've got to make these things biocompatible either biocompatible in the sense that we're going to put our robots out into the environment and they're going to have to be compatible with the environment but also if you want to put it inside the human body it has to be safe as well okay so in our laboratory we're interested in all types of soft robotics and to do that we look at these new materials some of which work at high voltages and there be quite strong some of them like the ones we've got here work at much lower voltages and they're not quite so strong but they really do move quite a lot now because they're low working at lower voltages that's quite attractive for some immediate applications where the high voltage applications are high voltage actuators and materials we've got to be we've got to work on those quite a long time before we can start using those in medical applications and so on but these low-voltage actuators the ones I'm going to show you now they're really quite suitable for use immediately so this one is working at a voltage of about 2 or 3 volts the kind of voltage that we're now enable us to put these materials into the human body so what I'm going to do is I'm going to show you this material which is a polymer but it's covered on both sides with the gold electrode and the gold electrode is soft enough and it's been configured so that when the material bends the gold doesn't break that maintains conduction so what happens when I apply electricity to this now when I put my voltage across these membranes they Bend well some of the materials we've got will expand and then we can look at them as artificial chromatophores color-changing devices and so on but these ones are really quite special because they've bent and flex and then we look at them we think I'll actually that's quite interesting we can use them for applications for example for swimming so here we can make swimming robots and we could do all sorts of interesting things here in this case we have a robot which looks a little bit like an enemy or a jellyfish or something like that and what's happening is that there's a beating action where the water is being pumped from one side to the other ok so this is a type of smart material that we call an ionic polymer composite material it's got gold on the outside and it's got a wet polymer on the inside and then all we need to do is take our box which is applying all 2 volts or 3 volts or so and you can see that it bends and twists now it's moving an awful lot and that involves some interesting motion of the ions inside the material but you also see when I hold down the voltage it moves one way and it comes back again so they're really interesting properties here which we need to assess and we need work with of course we can take this material we can configure it into some really interesting structures and if I hold up one here I've got an example which is like a snake structure and so you can see there there's one two three four five segments and if we I apply electricity to each one of those segments in a different way in a different order we can get this structure to swim backwards and forwards like this so this here it becomes the body of a robotic organism or a snake robot with no motors with nothing else in there just with that and of course all we need to do then is to put a controller or a head onto the robot put a power supply on and then we can get this thing to swim so the very attractive very interesting structures not only that we can make these things really quite small they can be miniaturized down to the micro and even to the nanometer level so they're very attractive materials again if we're going to use these materials we still have a fair amount of work to do in perfecting the chemistry so we need to work with the chemists looking at the mechanics of the structure and also working out what's the best way to use them which is really quite interesting that challenge so where before we saw the cuspid actuator 2-star actuator which was really quite large here i've got an example which is much much smaller and we can see that one so that's only about a centimeter across and when I put electricity on this one those little star shapes in the middle will open and close open and close so we've got a valve here on an active valve which looks a little bit like the valves inside the heart inside the heart there's a cuspid valve which is made from three parts that opens like a leaf like so and in this case we can apply electricity and we can have an active valve something which is a which is beyond nature we will have to see whether we can use this for lots of interesting applications possibly with pumping fluid for moving things around or even to control the flow of fluid

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