The essential question when it comes to polymer science is that if you begin with a clear liquid and end up with a clear liquid have accomplished anything and is it different from your previous accomplishment? The solution to that question can be determined through polymer characterization.
This field will determine whether you have made anything, whether it is what you intended to make and if it is the same thing you made earlier. Throughout the process, you will also find the answers to even more questions that you did not previously know to ask.
Characterization is defined as the description of qualities and peculiarities. Now, you may be wondering just how to describe a polymer. You could describe the position of the atoms, the angles of conformation or their bond lengths. You would do this for each molecule of the polymer solution.
The simple fact is that you must settle for averages of the qualities that you choose to measure. Therefore, in order to achieve polymer characterization, you will first need to understand what those qualities might be.
Molecular Weight
This refers to the molecular weight of the specific polymer molecule. However, it is easy to see that the odds of all polymer molecules that have the same number of subunits are quite high. Generally, the molecules will have a range of molecular weights. This is known as polydispersity. Therefore, you measure some average of molecular weight, depending on the technique used for the measurement.
For the polydispersity, you will need to determine a method for characterizing the distribution of molecular weights. One method is to measure and record the whole distribution of molecular weights. However, a simpler technique would be to express the polydispersity as a ratio of various molecular weight averages.
Another measurement of polymer characterization is the size or radius of gyration. This is in reference to the physical extent of each molecule, such as the amount of room it uses. It quickly becomes clear that the stiffer molecules take up more room for their given molecular weight than the molecules that are more flexible.
With this issue, you will need to carefully define size. For instance, you can determine if an electrostatically charged molecule takes up more room than a neutral molecule. You will also be able to determine what will happen when the ionic strength of the environment is changed.
