Super-resolution localization microscopy reveals nanoscale dynamics of polymers and soft matter

Super-resolved astigmatic microscopy allows 3D spatial localization of individual molecules of fluorescent dyes with nanometer accuracy. Apart from imaging, such localization has found applications in the study of nanometer-scale physical properties of polymers and complex soft matter. Here, we introduce the principle of the astigmatic imaging and present examples of its use in the study of polymers and liquid crystals. Study of relaxation dynamics across thin polymer films shows that the effect of substrate is dominant over the surface effect in determining the thin film properties below the glass transition temperature. Monitoring of diffusion in nematic liquid crystals reveals position-dependent changes in tilt angle, confined diffusion close to the liquid crystal cell wall and reorientation of the liquid crystal director close to a nanoparticle. Study of diffusion in polymer films above the glass transition shows that the film substrate causes considerable slow-down in the diffusion and that this effect extends up to 200 nm into the bulk of the film.