Masters Thesis work vs Phd Work I had a doubt regarding research. I want to pursue a masters degree. I have a few topics I want to do research in.  In my case its advanced materials like polymers, macromolecules and also in energy storage applications. For my masters thesis work I am getting to work in the field of polymers and self-assembly. However, I am not sure which field I would like to pursue over long term, but surely it would be in between these topics. Can I shift my topic of research when I apply for a Phd or does my research has to be connected and aligned in order for a professor to accept me for a Phd. If anyone can help then it will help me make an informed decision.
Of course you can! 

It is absolutely normal for especially young people that they do not yet know what their best and greatest interests are. Don't be afraid of those that try to spread fear with nonsense like 'straight carrer-lines'. Nowadays, job recruiters more and more value those that have the self-confidence, curiosity and intellect to focus on more than only one topic and demonstrate through this that they can work themselves in difficult topics even if those have nothing or few in common.

And to make a personal advice: It's your life, so do not forget to have fun besides going for a carrer. The decision of a Professor is absolutely individual; there might be some, that want to see some work in the field, maybe, that I heard about a lot of people that started writing about stuff they have never even heard about before they applied, so yes, it is not uncommon to change the topic for PhD work. I believe that they mostly much more want to see your effort and talent, oh, and it's about sympathy, of course, as you will see each other quite often (not in all cases, but at my university that's very common). If you are worried, simply go and ask your Professor of choice what his or her expectations are. If (s)he is fair, he will let you know very clearly what he expects and will give you a chance beside the master thesis you wrote to show your talents. A master work in the same field can of course draw the attention of a specific Professor beforehand if it was really good, but there are enough other ways to put yourself to be short-listed.