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To a researcher dealing with long chain molecules, the term “random walk” signifies one of
the most common starting descriptors to understand the chain conformation of long string-like
molecules. However, the title I have chosen is more to describe the path my students and I
have taken during the past few decades to solve a variety of interesting problems in polymer
science; some of which have had to do with countering the strong tendency of polymer chains
to adopt random-coil conformations. Constructing polymer molecules that are not long string-
like objects but are more like highly branched trees possessing a “branch-upon-branch
topology”, has been one of our major preoccupations; in this context, we have developed novel
methods to prepare such highly branched polymers that are called “hyperbranched polymers
(HBPs)”, examined the effect of branching density on their chain conformation, created and
explored core-shell type HBPs, examined the curious case of Janus (two-faced) HBPs, etc. A
later preoccupation of ours has been to develop strategies to resist the strong tendency of
polymer chains to adopt random-coil conformations and consequently generate specifically
folded conformations using weak non-covalent interactions between periodically spaced
segments along the polymer backbone. This journey has led us to explore the use of charge-
transfer interactions, solvophobic exclusion, metal-ion coordination, alkylene segment
crystallization, etc., in an effort to get to the yet-elusive goal of translating the ordering in
solution on to the solid state.
In this talk, I shall describe some of the selected early explorations, along with some more
recent ones that deals with the demonstration of cross-stitched folded chains and the
development catalytic reaction vessels, wherein the reactants can be stirred in them, products
poured out and the vessel reused, after a simple solvent wash. If time permits, I shall also
discuss some of our failed attempts, as I believe there is more to be learnt from failure than
successes. The talk will truly showcase our random walks in research that provide us with the
most joyous moments of discovery. |