Real-Time High-Resolution AFM of Crystallization Process of Isotactic Poly(methyl methacrylate) Monolayer under High Humidity

We have successfully observed the formation of a folded-chain crystal (FCC) from an amorphous state at the molecular level using atomic force microscopy (AFM). We previously showed that FCC of an isotactic poly(methyl methacrylate) (it-PMMA) formed in its Langmuir monolayer upon compression and after being deposited on mica could be visualized at the molecular level by AFM (Kumaki et al. JACS 2005, 127, 5788; J. Phys. Chem. B 2013, 117, 5594). Recently, we found that an amorphous it-PMMA monolayer deposited at a low surface pressure crystallized under high humidity at room temperature, and successfully visualized the FCC formation process at the molecular level by AFM in real time. We will discuss the various crystallization processes observed at the molecular level and their dependence on the humidity and the surface pressure during the deposition.