Bowls, vases and goblets-the microcrockery of polymer and nanocomposite morphology revealed by two-photon optical tomography.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34417451.
- Also identified by DOI 10.1038/s41467-021-25297-w and PMC identifier 8379155.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
On the >1 µm scale the morphology of semicrystalline plastics like polyethylene or Nylon features spherulites, "shish-kebabs", cylinddrites and other crystalline aggregates which strongly affect mechanical and other material properties. Current imaging techniques give only a 2D picture of these objects. Here we show how they can be visualized in 3D using fluorescent labels and confocal microscopy. As a result, we see spherulites in 3D, both in neat polymers and their nanocomposites, and observe how unevenly nanoparticles and other additives are distributed in the material. Images of i-polypropylene and biodegradable poly(lactic acid) reveal previously unsuspected morphologies such as "vases" and "goblets", nonspherical "spherulites" and, unexpectedly, "shish-kebabs" grown from quiescent melt. Also surprisingly, in nanocomposite sheets spherulite nucleation is seen to be copied from one surface to another, mediated by crystallization-induced pressure drop and local melt-flow. These first results reveal unfamiliar modes of self-assembly in familiar plastics and open fresh perspectives on polymer microstructure.