This article describes some of the progress made in the understanding of the growth of polymer lamellae and spherulites using atomic force microscopy (AFM) in the last five years. High-resolution and real-time AFM phase imaging enables us to observe the detailed growth process of lamellae. During the early stage of crystallization, embryos appear and disappear on the film surface. A stable embryo develops into a single lamella, which develops into a founding lamella. Then, the founding lamella develops into a lamellar sheaf through branching and splaying. Through further branching and splaying, a lamellar sheaf develops into a spherulite with two eyes at its center.

Thin films of poly(bisphenol A-co-decane) (BA-C10) were isothermally crystallized at different temperatures. The lamellar structures and branching during crystallization were observed in real time at different temperatures by an atomic force microscope equipped with a high-temperature heater accessory. Our observations indicated that induced nuclei developed into subsidiary lamellae, forming lamellar branches. Lamellar branches occurred randomly on the parent lamellae at high degrees of supercooling. However, lamellar branches were seldom observed at crystallization temperatures near the melting point. The minimum induction time for induced nucleation was found to occur at around 55℃.

The dynamic growth processes of lamellae and spherulites of a polymer (BA-C8) synthesized by condensation polymerization of bisphenol A and 1,8-dibromooctane were directly observed using an atomic force microscope at 25±1℃. The phase shift measured at the tip of growing lamellae is lower than the phase shifts of the other regions of the lamellae. This result indicates that the growth front of a lamella is softer and contains more defects than the developed ones. The growth process of lamellae and the formation of spherulites were studied. A lamella was observed to breed more lamellae by inducing adjacent secondary nuclei and to develop into a lamellar sheaf and finally into a spherulite. The lamellae were preferentially oriented edge-on with respect to the surface of the BA-C8 polymer thin films. The detailed observations on the formation of the secondary nuclei indicated that the branching of the lamellae was only a temporary growth stage of the secondary lamellae. At the branch point, the secondary lamellae could propagate in both backward and forward directions with respect to the growth direction of the parent lamellae.

Poly(para-phenylene vinylene) with crown ether substituents (C-PPV) could form nanoribbons through supramolecular assembly with K+ in dilute chloroform solution. The length of the nanoribbons increased with an increase in the standing time of the C-PPV/K+ solution. Experimental evidence to support the interaction between K+ and crown ether substituents was provided, and the growth mechanism of C-PPV/K+ nanorods to nanoribbons was proposed. The influence of the length of the nanoribbons on the photophysics of C-PPV was also investigated.