Carbon nanotubes have been known to develop hierarchically ordered polymer nanocomposites by virtue of epitaxial crystallization. A unique product of CNT induced crystallization is generation of nanohybrid shish-kebab (NHSK) structure, which has gained tremendous attention owing to its unique applications. However, research faces major challenges in terms of producing tunable patterns on CNTs, which are largely governed by precise control of the crystallization parameters. Conventional methods of experimentation can mislead the effect of experimental conditions on NHSK structure. The effect of crystallization time, undercooling temperature and polymer concentration on the NHSK architecture of carbon nanotubes (CNTs) and on a block copolymer, polyethylene-b-polyethylene glycol (PE-b-PEG), was studied in this work by applying the Response Surface Methodology (RSM). The present novel investigation mainly reports the statistical models that can be used to predict the different NHSK structural features such as diameter, periodicity, and thickness by including the interaction and quadratic effects of experimental variables. The developed models are in very good agreement with the experimental data and are statistically significant. Our novel approach can be used to better understand the interplay between various crystallization parameters for periodic patterning on carbon nanotubes to generate tunable hierarchical structures.
A comparative study of the effect of copolymer composition on nanohybrid shish‐kebab (NHSK) architecture on carbon nanotubes (CNTs) is presented. A semi‐crystalline amphiphilic di‐block copolymer, polyethylene‐b‐polyethylene glycol (PE‐b‐PEG) was used in this study. Copolymer composition was varied on the basis of the molecular weight of individual copolymers and the ratio between PE and PEG. NHSK structure was characterized using a combination of scanning and transmission electron microscopy. The mobility of PEG, which is determined by its chain length was found to have a significant impact on the periodic decoration of the copolymer on CNTs. With higher chain length or molecular weight, PEG chains provided better stability to micelles formed by the copolymer. Further, PEG assisted micellar stability to create a foundation for PE chains to interact and orient along the tube axis of CNTs as a function of the copolymer composition. It was found that the stability of NHSK architecture can also be changed over time at the same crystallization temperature. This work offers novel and fundamental insights towards the mobility of PEG in the copolymer and its disk‐shaped crystal's formation and micellar stability during crystallization with CNTs. This study provides a better understanding of a mechanically tunable NHSK where the architecture of copolymer crystals can be modified by adjusting the molecular weight of PEG.
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