In Situ Observation of Crystal Growth for Poly[(S)-lactide] by Temperature-Controlled Atomic Force Microscopy

Abstract

The crystallization behavior and crystalline morphologies of poly[(S)-lactide] (P[(S)-LA]) in thin films crystallized isothermally at over 160 degrees C were characterized by transmission electron microscopy and atomic force microscopy (AFM). The dendritic crystal and hexagonal crystal were formed in thin film with thicknesses below 30 nm or over 50 nm, respectively. The crystal structures of dendritic and hexagonal crystals were identical, suggesting that the crystalline morphology of P[(S)-LA] is strongly dependent upon the film thickness. In situ observation of the crystal growth in the P[(S)-LA] thin film at 165 degrees C from the melt was carried out by using temperature-controlled AFM equipped with a heating stage. The initial stage of crystallization and development of lamellae were successfully observed during isothermal crystallization at 165 degrees C. The first forming crystal showed the edge-on orientation, and grew to S-shaped edge-on lamellae. Dendritic flat-on crystals were developed from the S-shaped edge-on lamellae. The growth rates of flat-on and edge-on lamellae were almost identical.

Scanning Force Microscopy as Applied to Conformational Studies in Macromolecular Research

“…One can mention, e.g., real time visualisation of stages of such dynamic processes as melting [188][189][190] and crystallisation [191][192][193] in thin polymer films as well as growth of elongated oriented crystallites. [194,195] In such experiments variable temperature of the polymer sample serves as a tool to unfreeze required dynamics to be followed in real time with SFM. [196,197] In a similar manner, dewetting [198] processes of ultrathin polymer films were studied in real time regime.…”

Crystalline and Spherulitic Morphology of Polymers Crystallized in Confined Systems

“…Interestingly, the transition of lamellar orientation from edge-on to flat-on could take place when the edge-on lamellae were created by rubbing or scratching amorphous polymer films using AFM tips [43,[64][65][66], but the accurate value of transition thickness was still unknown [40]. The readers can refer to [40,[66][67][68] for more detailed discussion on this aspect. film with high molecular weight showed branches on one side of the stems; yet, that with lower molecular weight exhibited the branches on both sides of the stems.…”

Effect of bisphenol A on the miscibility, phase morphology, and specific interaction in immiscible biodegradable poly(ε‐caprolactone)/poly(L‐lactide) blends

“…1 Poly(llactide) (PLLA) has been studied intensively and used widely in these applications because of its high biocompatibility and good biodegradability. 2,3 Nonetheless, one major disadvantage of PLLA is the transition from ductile to brittle failure under tension as a result of its high melting temperature. In contrast, poly(-caprolactone) (PCL) possesses low glass transition and melting temperatures and has been added to PLLA in the role of a plasticizer to render it more flexible and to reduce its brittleness.…”