 Okay, so we'll start with polymers. Okay. What is a polymer? Any idea? Anything you can say about this? Association of molecules. Association of molecules. Any example of polymers? Nylon. Like no, in daily use. Anything that we use, which is, which comes under this category? Tell me. No idea. Can it be like an organic polymer also? Anything. Sucrose. What? Sucrose. Okay. Okay. What about the bottle that we use, water bottle? Is that a kind of polymer? The wire that we use, the cable wire. Okay. The laptop, this buttons that you have. Keys. Or this, a material of this laptop. Okay. Cable wire that we have. Any kind of wire you see, switchboard is the kind of polymer. Plastic box that we use in kitchen to keep those, you know, pulses and spices and all. Those plastic box are also a kind of polymer. Okay. Anything. Like polymers is a very vast application in our day-to-day life. Every day we use different different kinds of polymers. Okay. So that's why, you know, the application of this is very huge in our day-to-day life. That's why this industry is very big. Polymer industry is very big. Okay. The fiber pipes that we have. The pipe that we use for the flow of water. From the water tank to, you know, in the tap and on kitchen everywhere, washroom, wherever we use those pipes. Okay. So all those materials comes under the category of polymer. Okay. Depending upon the strength required for a given purpose, we build the polymer and then we use it. Okay. So that's why, like I said, the industry is very big. And we, on a daily basis, we use these kind of polymers. Okay. So that's why when you do some research work, masters in polymer technology and all, there is a very good scope of, you know, good career opportunity we have. Because like I have given you many examples that comes under polymers and we use daily in our life. Okay. So that's how the thing is like. So polymers are what? Polymers are made up of two or more different kinds of molecules. Okay. Different or same kinds. Anyone you can take. Okay. Two or more different or same kind of compounds. These compounds are the basic constituents. Okay. The basic constituents of the polymers and we call it as monomers. Okay. You must have heard about monomer, dimer and all. Right. So dimer comes under the category of polymer because we define what when two or more substance combines together to give a large complex structure that compound is known as polymer. Okay. So application of polymers uses we have discussed. Okay. Now we are going to see in this chapter, the chapter is theoretical. Okay. You won't get any numerical question to this. The point is you need to know for a given compounds, what is the monomer of that? Okay. What kind of linkage is there? What is the repeating unit in the polymer? Okay. Those things you have to keep in mind. Okay. And since it is, we're doing this in chemistry. So we also have to see the reactions which involves in the formation of polymers. Okay. But like I said, reactions hardly they ask in this. They will ask you the monomers of different polymers, the repeating unit. Okay. And what kind of linkage is there? Sometimes they ask because all those things will discuss one by one. First of all, you'll write down the definition of polymers definition you write down write down polymers are polymers are a very large complex molecules. Polymers are very large complex molecules, which has, which has very high molecular masses, very high molecular masses, masses, and each molecule consists of each molecule consists of each molecule means polymer molecules. Each molecule consists of a very large number of simple, a very large number of large number of simple structural units, structural units joined together, structural units joined together through covalent bond to covalent bond. These structural units next line, write down these structural units that you have each of these structural units are called monomers are called monomers. Okay. Next line, the method or process by which process by which monomers are monomers converts into monomers converts into polymers are called polymerization technique are called polymerization technique. And this phenomenon is polymerization. So this is the definition of polymer. Okay. But definition obviously they won't ask examples of polymers. I have given you many examples. Write down the examples are we have a polyethylene polyethylene is nothing but polythene that we use the plastic bag. Okay, we can have polyvinyl chloride PVC. We can have a nylon 66 etc. There are many other things. Okay, plastic bag, plastic box, okay, cable, okay, the electric board switches. All these are examples of polymers. Okay, which are there in day to day life that we use. Okay, now what I said polymers are made up of made up of what to or more monomer basic structural unit, which we call it as monomer to or more basic structural unit known as monomers. Okay, so these are polymer can take same type of monomer also a different type of monomer. Okay, the polymers again we can classify this polymer into two types. Okay, based upon based upon based on the structural unit present and a structural unit means what the monomers. Okay, based upon the structural unit present two types of monomers we have sorry polymers we have based on the structural unit. The first type, we call it as homopolymers, homopolymers. And the second one is copolymers. In homopolymers, the repeating structural unit this you have to memorize this you have to keep this in mind. The repeating structural unit are derived from only one type, only one type of monomer units, only one type of monomer units. Okay, same monomer will have in this. Okay, we cannot have different monomers. Like you see polyethylene I have written here one example. Okay, the monomer of polyethylene is ethylene and that's why the polymer of ethylene is polyethylene. Got it polymer of propylene is polypropylene. Okay, like that we write down the name. So with this polyethylene what if somebody asks you what is the monomer here remove this poly you'll get the name of the monomer that is ethylene. Okay, so polyethylene is a type of homopolymers. That's what you have to memorize. Okay, they may ask you this question. They'll give you four options and they say which one of these is homopolymer or copolymer. Okay, so you should know the definition of it. What is homopolymer? What is copolymer? Then only you can say whether the repeating structural unit which is nothing but monomers. Okay, we have either we have same type of monomers or different types of monomers. Okay, we are not concerned with the number of monomers present but we have to see like whether we have same kind of monomer like in polyethylene or different kind of monomer I'll give you the example of that. Okay, so homopolymers are those polymers where the repeating structural unit are same only one type of repeating structural unit here. Copolymer it is reverse of it. In copolymers what happens we have different repeating structural unit. Okay, with the two monomer that we use here or simply in one line we'll write down. For copolymers we use different types of monomers of structural unit which is monomers. Got it? The example of copolymer is nylon 66. We'll do one by one the different polymers we have and then there also we'll see this one is homopolymer this one is copolymer. Just you copy it down first. Copy it sir. Done sir. Done? Okay.