Polymer Crystallization and Morphology in Thin Films

Polymer crystallisation and morphology in thin films underpin the performance of a broad range of modern materials, from flexible electronics and barrier coatings to biomedical devices and sustainable packaging. When confined to nanometre-scale thicknesses, semicrystalline polymers assemble into lamellar stacks, spherulitic aggregates or oriented fibres, with chain alignment, crystal thickness and long-period spacing strongly influenced by film thickness, substrate chemistry, interfacial interactions and thermal history. The nucleation process within these films may proceed homogeneously in the bulk or heterogeneously at interfaces, yielding variations in crystal orientation and density that critically govern mechanical strength, optical clarity and barrier properties. Advanced characterisation techniques—such as grazing-incidence X-ray scattering, electron-diffraction imaging and atomic force microscopy—now enable in situ observation of lamellar stacking and chain tilt at nanometre resolution. Through controlled annealing, solvent vapour treatment or epitaxial templating, it is possible to tailor the hierarchical arrangement of polymer chains, achieving bespoke thin-film architectures with optimised crystallinity and morphology. Such advances inform rational design of next-generation polymer coatings and functional surfaces with precise control over thermal, electrical and degradative performance.

Research from Nature Portfolio

Recent studies have provided new insights into chain orientation within nanometre-thick lamellae and the melting behaviour of ultrathin polymer layers. Using state-of-the-art electron-diffraction-based imaging, investigators have directly visualised molecular-chain orientations in the lamellar crystals of high-density polyethylene, revealing nanoscale variations in chain tilt that challenge longstanding folding models and offer routes to fine-tune mechanical and barrier properties. In parallel, research on monolayers of ultralong alkane chains demonstrated that, when confined to two dimensions, melting can proceed in a quasi-continuous manner. Atomic force microscopy and mean-field theory revealed reversible movement of the crystal-melt interface and a gradual decline in equilibrium crystallinity well above the bulk melting point, highlighting fundamentally different transition pathways in thin films compared with bulk polymers.

Polymer Crystallization and Morphology in Thin Films publication trend

The graph below shows the total number of articles in polymer crystallization and morphology in thin films across all publications each year (not limited to Nature Index journals).

Technical terms

Lamellar crystal: A plate-like polymer crystal in which chains fold periodically, forming ordered layers of crystalline and amorphous regions.

Nucleation: The initial formation of a stable crystalline nucleus, either homogeneously within the bulk or heterogeneously at an interface or impurity.

Epitaxy: The directed growth of a crystal film on a substrate whose lattice structure guides the orientation and ordering of the overlying layer.

Grazing-incidence X-ray scattering: A surface-sensitive diffraction technique used to probe in-plane and out-of-plane ordering of thin films at nanometre resolution.

Spherulite: A roughly spherical aggregate of radially oriented lamellae formed during polymer crystallisation, often seen in thicker films or bulk samples.

References

1. Reassessing chain tilt in the lamellar crystals of polyethylene. Nature Communications (2023).
2. Quasi-continuous melting of model polymer monolayers prompts reinterpretation of polymer melting. Nature Communications (2021).
3. Epitaxy‐Directed Self‐Assembly of Copolymers and Polymer Blends. Advanced Science (2023).
4. Synthesis, Morphology, and Crystallization Kinetics of Polyheptalactone (PHL). Biomacromolecules (2023).
5. Heterogeneous Crystal Nucleation from the Melt in Polyethylene Oxide Droplets on Graphite: Kinetics and Microscopic Structure. Crystals (2021).