Single‐molecule methods in polymer science

Abstract

No one can forget the exhilaration of seeing an individual molecule or atom for the first time, or of manipulating one. Like children we use them as building blocks—think of writing with ink made of single atoms by using scanning tunneling microscopy and of constructing complex origami by using DNA. Or, like a voyeur, just watching single molecules go about their business. To those who studied quantum mechanics with a reflective turn of mind, this may seem magical and seem to risk violating the laws of quantum mechanics, but it does not. This viewpoint will focus on single-molecule fluorescence methods and leave for another day the equally interesting problem of single-molecule force measurements, for example, the tour de force of measuring the stress–strain properties of individual chains. We will focus on how the problems of polymers differ from those of biophysics, where single-molecule fluorescence methods have had so much impact. We emphasize unsolved problems and areas for useful future research.