This research introduces an innovative approach for evaluating the degree of densification of carbon nanotube (CNT) sheets produced through direct spinning and subsequently treated with organic solvent (specifically ethanol). Analysis of the morphological features of the CNT sheets from the FE-SEM image affirms that the sheet’s structure becomes more densified following the treatment. Based on this, the treated CNT sheet was comprehensively evaluated using Raman spectroscopy. The results indicate a downward shift in the G′ band, signifying the densification of the CNT sheet’s structure due to the C–C bond weakening by the cohesive force. Following ethanol treatment, the CNT sheet exhibited enhanced electrical conductivity and tensile strength, measuring approximately 1.7 × 105 S m− 1 and 138.7 MPa, respectively, a remarkable improvement of roughly 300% compared to the untreated CNT sheet. This study underscores the efficacy of Raman spectroscopy as a powerful tool for assessing the densification of CNT sheets.

Assessment of carbon nanotube sheet densification level
    Abstract
    1 Introduction
    2 Materials and methods
        2.1 Fabrication and densification of CNT sheet
        2.2 Characterizations
    3 Results and discussion
    4 Conclusion
    References

• Nilüfer Çakmakçı(Department of Materials Science and Engineering, Soongsil University, Seoul 06978, South Korea)
• Byungkwon Yoo(Department of Materials Science and Engineering, Soongsil University, Seoul 06978, South Korea)
• Hosin Lee(Department of Materials Science and Engineering, Soongsil University, Seoul 06978, South Korea)
• Youngjin Jeong(Department of Materials Science and Engineering, Soongsil University, Seoul 06978, South Korea, Department of Green Chemistry and Materials Engineering, Soongsil University, Seoul 06978, South Korea) Corresponding author