resumo
The rising interest in biodegradable polymers like PLLA is gaining attention for their potential in next-generation biomedical devices. One of the critical challenges in leveraging PLLA's full potential is enhancing its crystallinity, as it greatly influences mechanical, thermal, degradation, and piezoelectric properties, which are essential for various applications. Here, we use thermal annealing and strain engineering to transform the amorphous phase into a more ordered crystalline structure. Through various characterization techniques, we show that crystallinity increased progressively from 34.8% in unprocessed films to 57.4% at 100% strain. Terahertz time-domain spectroscopy is employed to gain insights into the structural and dynamic properties where we study low-frequency molecular vibrations and anisotropic properties, enabling simultaneous evaluation of structural, such as crystallinity, and optical characteristics. Rotational analysis provides direct evidence of molecular orientation and birefringence induced by mechanical processing. These findings align strongly with the traditional characterization techniques (XRD, WAXS, DSC, and FTIR). Piezoresponse force microscopy shows that the VPFM signal increased from 0.65 +/- 0.15 pm V-1 in unprocessed films to 6.5 +/- 1.5 pm V-1 at 100% strain. The in-depth work is an important step in gaining a deeper understanding of how the crystalline regions form, evolve under different processing conditions, and influence PLLA's overall properties.
palavras-chave
BETA-FORM; CRYSTAL-STRUCTURE; ALPHA-FORM; BEHAVIOR; SPECTROSCOPY; MORPHOLOGY
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Merhi, Y; Goumarre, V; Romanyuk, K; Amarasinghe, Y; Kholkin, A; Klarskov, P; Agarwala, S
nossos autores
Andrei Kholkin
Investigador Jubilado
Konstantin Nikolaevich Romanyuk
Investigador JúniorProjectos
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
agradecimentos
The project is funded by the Independent Research Fund Denmark under Grant 1032-00182B. AK acknowledges the project FeLow-D funded under the Horizon Europe programme HORIZON-WIDERA-2023-TALENTS-01, GA no. 101186499. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI: https://doi.org/10.54499/UIDB/50011/2020), UIDP/50011/2020 (DOI: https://doi.org/10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI: https://doi.org/10.54499/LA/P/0006/2020), financed by national funds through the FCT/MCTES (PIDDAC).