Which process involves linking mers of different kinds in the same addition chain?

The correct choice is copolymerisation, as it specifically refers to a process where two or more different types of monomers (mers) are linked together to form a copolymer. In this context, the term "addition chain" indicates that the resulting polymer is created through an addition reaction, where monomers are directly added to each other without the loss of any small molecules like water or alcohol.

Copolymers exhibit unique properties derived from the combination of the different monomers, thus allowing for enhanced performance in various applications compared to homopolymers, which consist of a single type of monomer.

The other processes mentioned do not focus on the linking of different kinds of mers. Polymerisation generally refers to the process of forming a polymer from monomers, without specifying whether they are of the same or different kinds. Condensation involves a reaction that results in the release of a small molecule, typically water, as the monomers join; this is a different mechanism than what is used in copolymerisation. Chain reactions typically describe a sequence of reactions where the product of one step is the reactant for the next, rather than the specific linking of different types of mers.

Understanding copolymerisation is key to materials science,