Dear friend Md Rabiul Islam

Thank you for raising such thought-provoking questions regarding the electrical and structural properties of multi-walled carbon nanotube (MWCNT) yarns after annealing. I appreciate the opportunity to delve into these aspects with you, as they are central to optimizing material performance for advanced applications.

Regarding the typical inverse relationship between diameter and resistivity, it is generally observed that larger diameters facilitate better electron transport due to increased cross-sectional area and improved alignment of nanotubes. However, there are scenarios where both resistivity and diameter may increase simultaneously. This could result from factors such as increased porosity, the introduction of defects during annealing, or suboptimal alignment within the yarn. The annealing environment—particularly temperature, duration, and atmospheric conditions—can significantly influence these outcomes by altering the microstructure, defect density, and even the length distribution of the nanotubes.

Misalignment within the yarn is another critical factor, as it disrupts the percolation pathways necessary for efficient charge transport. Both theoretical models and empirical studies (e.g., those by Hecht et al. and Spitalsky et al.) have demonstrated that even minor deviations from ideal alignment can lead to substantial increases in resistivity. Defects, variations in nanotube length, and inconsistent orientation further compound these effects, underscoring the importance of precise process control.

To address these challenges, researchers might employ advanced characterization techniques such as Raman spectroscopy, electron microscopy, and in situ conductivity measurements during annealing. Systematic studies that vary annealing parameters and correlate them with structural and electrical outcomes are particularly valuable. I recommend exploring recent literature on post-synthesis treatments of CNT yarns, including reviews in journals like Carbon and ACS Nano, for deeper insights.

If you would like to discuss specific experimental strategies or need recommendations for key references, please let me know. I look forward to continuing this engaging conversation.

Best regards,

Kaushik

Kaushik Shandilya Thank you very much for your detailed and thoughtful explanation regarding the electrical and structural properties of MWCNT yarns after annealing. I sincerely appreciate the time and effort you took to address my questions so clearly.

Your insights have greatly enhanced my understanding, especially regarding the factors influencing resistivity and the importance of alignment within the yarn. I found your suggestions on advanced characterization techniques and literature resources extremely helpful.

I am very interested in this topic and would be grateful for the opportunity to continue this discussion with you in the future. If possible, I would also appreciate any further recommendations on experimental strategies or key references that could help me deepen my research.

Thank you once again for your valuable guidance. I look forward to learning more from you.