Yes, hello everyone, my name is Sven Dixander Barker, I am a researcher and PhD student at the Institute for Multiphase Processes at Leibniz University of Hanover, Germany.

Today I would like to tell you something to our DSC. DSC stands for Dynamic Scanning Calorimetry. So in principle what we can do is we can investigate our thermal properties of our material liquids and analyze them with this device. Ok, so let's talk about the brief setup and the function of this device.

So we have here our main instrument where we will do the main analysis. Connected to that we have a liquid nitrogen tank here to enable us to cool the chamber inside the main device. So we can fill in here up to 50 liters of liquid nitrogen and as you have already

heard or maybe have heard we have to look at different safety instructions for handling with liquid nitrogen. Situated on top of this tank is a pump which then pumps the liquid nitrogen through the tubing into the main device.

Next to the main device we have a controller unit which controls the pump and is connected to the main device. In the main device unit we have a small chamber, within the chamber we have a reference sample which is basically filled with air.

I will show you in a minute the cubicles where we fill our samples in and in here the reference is completely empty. Next to the sample then we place our main sample that we want to analyze and both samples are situated on small heating elements which also includes the thermal sensors.

And what happens during the process is that we heat or cool our sample and due to the different thermal transition between our sample and our reference we obtain different curves and through these

curves we receive our information on our thermal properties of our sample that we want to look at. Such as a heat of fusion, a glass transition temperature or also our melt temperature. The entire system here has to be also filled with normal nitrogen gas and to enable a safe handling of our materials that we want to look at.

So in the next section I will show you how to prepare the samples. So we have here the bottom side where our fiber mat sample will be placed in

and we have here the cup or the lid which will be then placed onto our pans. So what we have to do at the beginning is to take one pan and a lid and then we have to determine the empty weight of this combination.

So we put that on here and then we weigh the empty weight of lid and pan. So we then note this value 40.9 because we will need that for our later investigations of the thermal properties.

So in the first step of our sample preparation for this example I have decided upon using the fiber mat from made of polycaprolactone, PCL. So we want to look at this sample and its thermal properties. For that we have to cut a small sample out of our fiber mat and we have to encapsulate our sample within DSC pans made of aluminium.

So in the next step we have weighed now our empty pan and lid. So in the next step we have to cut our sample out of our fiber mat.

So we use tweezers for that and then cut an adequate sample out of here. So once we've cut our sample then we would weigh our sample so that we achieve a weight of around about 8 to 12 milligrams.

And then afterwards we have to place our sample within the aluminium pan. So this is the tricky bit because we have to try that the entire sample fills

out the bottom completely of our pan and that no fibers are sticking out on the sides. And then after that we put the lid on and so that the lid stays on our pan then we will close our sample within this sample holder.

Finally then we will weigh the sample again and therefore check if the first weighing of our initial sample is identical. Because we will need the sample mass and the mass of the lid and the pan so that the software can calculate our values.

So in the next step then we will put that into our device. So now we've weighed our sample, we know the weight of our material, we know the weight of our pan and lid.

So what we do now is we put our sample into the device but before that we have to remember because we want to look at our thermal properties. So with PCL for example very important is the melting temperature. And since we will determine that so that our sample is not destroyed in the device during heating we have

to make a small hole into the lid so that the residual air can get out of our sample container. So next we will place our sample within our device.

So we have to open the lid and there are a few chambers that we have to open. And now you can see inside we have here the reference I was speaking about which is empty and we have here the heating element and sensor where we will place our sample.

So we will take our sample and then place it on the heating element so that its location is identical to the reference.

And after that I will close the chamber again and we can continue with the set of parameters. So now we can insert our parameters. I've already done that.

So we've got our sample mass and we've got our mass of the lid and the aluminium pan. So we enter all these values. We enter our identity of our sample. So in this case it is PCL and then we will finally put in our temperature program.

So we will heat up our sample to 100 degrees centigrade since we expect our melting temperature at plus 60 degrees. Following that we will cool down the sample to minus 100 degrees centigrade since the glass transition temperature of PCL is expected to be by minus 60 degrees.

And then we will rewarm the sample again so we have two cycles where we will analyse our material finally. So when we've typed in the entire protocol then we just edit the last few things like whether we want to save it.

And when we've done that then of course we have to remember that we have to have liquid nitrogen in our tank so we would fill that into it. And then finally when that's done then we click on start and the process will start. So once our process is completely run through then we receive this curve and

it is the DSC signal in milliwatt per milligrams over the time in minutes. But since we want to have our temperatures we have to change our scale and there is a function in the software where we can change our scale. That means we've now got the DSC signal over the temperature.

With the software now we can choose which curve we want. So for example we will take the first warming period and here now we can determine by choosing the peak function the melting temperature which is 62.8 for this first heating.

We can also determine the energy of fusion by integrating the field underneath this peak and by doing that we receive an enthalpy of fusion of 71.73 joule per grams.

So on the basis of this we can then calculate our crystallinity because we know the crystallinity 100% crystal in PCL and therefore we can calculate then our crystallinity for our individual sample.

Now looking at the glass transition temperature we obviously need the cooling process so we choose then our cooling scenario. And since now we want to look at our glass transition temperature because with the first heating we obviously started at room temperature so it would cool everything down.

From that curve that we achieved through the cooling process we can determine for example the recrystallization temperature or also enthalpy. And when we want to look at the glass transition now we take the first complete heating from minus 100 to plus 100. And with the function we then, because we know that we expect the glass transition to be around about

60 degrees, minus 60 degrees so then we can determine an interval between minus 70 and minus 50 for example. And when we apply that we achieve here a glass transition temperature from minus 63.1 degrees centigrade for our individual sample.

And we would do that of course now for both cycles. For the first one we've just done it and for the second one then we would continue. And this shows now exemplarly how all parameters would look like when we have finally determined them and on the

basis of this then we can conclude our results about our specific material parameters which we have now looked at. Yeah so thank you very much for your attention and that was an overview of how you can

determine material thermal parameters by using the DSC which is a very valuable device to determine material parameters. Of course what I have not mentioned yet is of course we can use fluids that we can analyze but also solid materials. So that was just on the basis of the fibermat and of course we

can also look at different solutions, cryoprotective agents for example, how their thermal properties are. If you have any questions then don't hesitate to get in contact with us and yes, once again thank you very much for your attention and all the best.