Self Assembly of Block Polymer Systems
What is a block polymer?
Block polymers are two or more chemically distinct chain segments that are covalently bonded at one end. These segments often have a desire to demix completely but they cannot due to this covalent attachment. As a compromise, block polymers undergo a process known as microphase separation, where periodic arrays of domains are autonomously formed that are highly populated with each segment. Synthetically, we can tune block polymers to alter the size and shape of these domains which are often on the scale of 2-100 nm.
What can we do with microphase separated block polymers?
Block polymers offer the unique advantage of synergizing the salient properties of two different polymers into a single material. This is because both the constituent polymer segments separate into domains that are rich in each block. For example, we can create a material that is both hard and flexible by marrying together a rubbery and glassy block chemistry. It is also possible to utilize the different chemistries of the blocks to allow selective degradation or molecular diffusion on a domain. This allows advanced function, such as the creation of nanostructured patterns on a surface or selectively purifying molecular mixtures through a membrane.