Zhou Yingying, Firkowska-Boden Izabela, Arras Matthias M L, Jandt Klaus D
Chair of Materials Science, Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany.
School of Materials Engineering, Xi'an Aeronautical University, Xi'an 710077, P.R. China.
Langmuir. 2021 Jan 12;37(1):391-399. doi: 10.1021/acs.langmuir.0c03042. Epub 2020 Dec 23.
Block copolymers (BCPs) have previously been identified as powerful multiwalled carbon nanotube (MWCNT) dispersants in solution. However, relatively high costs and limited dispersibility hinder the use of BCPs in large-scale practical applications. Partial replacement of BCP with a low-cost homopolymer (HP) offers a promising approach to produce cost-effective MWNCT dispersions. The effect of HP/BCP blends on MWNCT dispersion degree and stability has yet to be elucidated. In this work, we tested the hypothesis that HP-induced BCP micelle size variation affects MWCNT dispersibility. Here, blends of the BCP poly(styrene)--poly(2-vinylpyridine) and the HP polystyrene (PS) were applied to examine BCP micelles' size dependence on the MWCNT dispersion degree. Light microscopy results showed that using HP/BCP blends, MWCNT dispersion was enhanced by up to 263% compared to pure BCP at a constant weight ratio of BCP to MWCNTs. Based on the correlation of increased MWCNT dispersion degree with increased BCP micelle size, as revealed by dynamic light scattering, an MWCNT dispersion mechanism is proposed. The mechanism includes a rationale for the unexpected finding that HP PS swells the BCP micelle's PS corona in a good solvent for PS. Using HP to increase MWCNT dispersion is a promising approach with possible applications in the production of high-performance composite materials. This holds especially for formulations of practical relevance where often (BCP) dispersants are only one of many components in the material.
嵌段共聚物（BCP）此前已被确定为溶液中强大的多壁碳纳米管（MWCNT）分散剂。然而，相对较高的成本和有限的分散性阻碍了BCP在大规模实际应用中的使用。用低成本的均聚物（HP）部分替代BCP为生产具有成本效益的MWNCT分散体提供了一种有前景的方法。HP/BCP共混物对MWNCT分散度和稳定性的影响尚未阐明。在这项工作中，我们测试了以下假设：HP诱导的BCP胶束尺寸变化会影响MWCNT的分散性。在此，将BCP聚（苯乙烯）-聚（2-乙烯基吡啶）与HP聚苯乙烯（PS）的共混物用于研究BCP胶束尺寸对MWCNT分散度的依赖性。光学显微镜结果表明，在BCP与MWCNTs的重量比恒定的情况下，使用HP/BCP共混物时，MWCNT的分散度比纯BCP提高了263%。基于动态光散射揭示的MWCNT分散度增加与BCP胶束尺寸增加之间的相关性，提出了一种MWCNT分散机制。该机制包括对一个意外发现的解释，即在对PS为良溶剂的情况下，HP PS会使BCP胶束的PS冠层膨胀。使用HP来提高MWCNT的分散性是一种有前景的方法，可能在高性能复合材料的生产中得到应用。这对于具有实际相关性的配方尤其适用，因为在这些配方中，（BCP）分散剂通常只是材料中的众多成分之一。
