At three different temperatures, T1, T2, and T3, the molecules in a liquid crystal align in these ways:

(a) At which temperature or temperatures is the substance in a liquid crystalline state? At those temperatures, which type of liquid crystalline phase is depicted?

Video transcript

Hello everyone today. We have the following problem. Consider the following behaviors of molecules of a liquid crystal at three different temperatures. T one, T. Two and T. Three identify the temperatures in which the substance exists in a liquid crystalline state and identify the type of liquid crystalline phase shown. So one thing that we should establish is the liquid phase. So in the liquid phase molecules are going to be arranged in a random fashion. So we can say that molecules are randomly spaced. This is because they have the freedom to do so. And so when it asks us to determine the type of liquid crystalline phase, it's asking us if it is either pneumatic or syntactic. So if it is pneumatic it is going to be in a fixed orientation and parallel. However the law, the ends are not gonna be lined up so it's just gonna be aligned in a fixed parallel fashion. It can also be we said smack tick so you can have smacked A and C. So in smack tic, A molecules are also fixed are also in a fixed orientation. So molecules are in a fixed orientation and they're parallel. However, the ends actually line up and we said in a pneumatic, the ends don't line up, maybe they don't align. And then we also have smack dick. See so in Semitic. See they're also fixed orientation, they're also parallel and there ends also line up and those quotes just mean that they are the same information asthmatic. A. However what's different with syntactic. See is that in syntactic, see the molecules are inclined at an angle. So these molecules are at an angle. So if we look at these individual ones, Let's look at T. 1 1st in T. One. These are going to be these molecules that we can see these pink molecules here they are in a fixed orientation. They are parallel But the lines but the ends don't necessarily align. So we can say T. one is a pneumatic phase. So this is a nomadic phase. If we look at T to this actually isn't a liquid phase at all. So this is not a liquid crystalline phase because while the molecules aren't in a random orientation they're just not aligned with each other, they're not fixed. So we can say that T. Two is not crystalline, we can say that T. Three is gonna represent a smack dick and which one C. Phase? Because they're in a fixed orientation. The molecules are parallel and the ends line up also they are inclined at an angle. So that's why it is syntactic C. For T. Three and pneumatic 41. And with that we've answered the question overall. I hope this helped. And until next time