Sivanantham M, Senthamaraikannan Ramsankar, Dirisala Anjaneyulu, Ghosh Chanchal, Ray Debes, Tewari Chetna, Padamati Ramesh, Choudhury Soumyadip, Jung Yong Chae
Research and Development Cell, Department of Physics, PRIST Deemed to be University, Vallam, Thanjavur 613 403, Tamil Nadu, India.
Department of Physics, P.R. Engineering College, Vallam, Thanjavur 613 403, Tamil Nadu, India.
Langmuir. 2023 Aug 8;39(31):10756-10768. doi: 10.1021/acs.langmuir.2c03364. Epub 2023 Jul 28.
This study demonstrates the multiple carbon morphology forming abilities of two dissimilar polyion complex (PIC)-based double hydrophilic block copolymers (DHBC) along with three different phenol concentrations when subjecting the blend in aqueous media via a hydrothermal-assisted carbonization strategy. The morphological transition from worm-like to spherical along with granular is found for the blend of oppositely charged poly(ethylene glycol) (PEG)-conjugated poly(amino acid) block copolymers, PEG-poly(l-lysine) (PEG-PLys) and PEG-poly(glutamic acid) (PEG-PGlu), along with three different concentrations of phenol. In contrast, after mixing the combination of PEG-PLys and PEG-poly(aspartic acid) (PEG-PAsp) separately with three different phenol contents, elliptical to irregular to spherical structural transition occurred. Fourier transform infrared and circular dichroism spectroscopic studies indicated that the formation of worm-like hybrid micellar structures is attributed to the presence of the β-sheet structure, whereas spherical-shaped hybrid micellar structures are formed due to the existence of α-helix and random coil structures. We discuss the mechanism for the secondary structure-induced morphology formation based on the theory related to the packing parameter, which is commonly used for analyzing the shape of the micellar structures. Secondary structures of the PIC-based DHBC system are responsible for forming multiple carbon morphologies, whereas these structures are absent in the case of the amphiphilic block copolymer (ABC) system. Furthermore, ABC-based template methods require organic solvent, ultrasonication, and a prolonged solvent evaporation process to obtain multiple carbon morphologies. Scanning electron microscopy observations suggested there is no significant morphological change even after subjecting the hybrid micelles to carbonization at elevated temperatures. Raman scattering studies revealed that the degree of graphitization and the graphitic crystallite domain size of the carbonized sample depend on the phenol content. Carbon materials exhibited the highest specific surface area of 579 m g along with a pore volume of 0.398 cc g, and this observation suggests that the prepared carbons are porous. Our findings illustrate the facile and effective strategy to fabricate the multiple carbon morphologies that can be used as potential candidates for energy storage applications.
本研究展示了两种不同的基于聚离子复合物（PIC）的双亲水嵌段共聚物（DHBC）在三种不同苯酚浓度下，通过水热辅助碳化策略使共混物在水性介质中时形成多种碳形态的能力。对于带相反电荷的聚乙二醇（PEG）共轭聚氨基酸嵌段共聚物、PEG-聚（L-赖氨酸）（PEG-PLys）和PEG-聚（谷氨酸）（PEG-PGlu）的共混物，以及三种不同浓度的苯酚，发现了从蠕虫状到球形以及颗粒状的形态转变。相反，将PEG-PLys和PEG-聚（天冬氨酸）（PEG-PAsp）的组合分别与三种不同苯酚含量混合后，发生了从椭圆形到不规则形再到球形的结构转变。傅里叶变换红外光谱和圆二色光谱研究表明，蠕虫状混合胶束结构的形成归因于β-折叠结构的存在，而球形混合胶束结构是由于α-螺旋和无规卷曲结构的存在而形成的。我们基于与堆积参数相关的理论讨论了二级结构诱导形态形成的机制，该理论常用于分析胶束结构的形状。基于PIC的DHBC体系的二级结构负责形成多种碳形态，而在两亲性嵌段共聚物（ABC）体系中则不存在这些结构。此外，基于ABC的模板方法需要有机溶剂、超声处理以及长时间的溶剂蒸发过程来获得多种碳形态。扫描电子显微镜观察表明，即使在高温下对混合胶束进行碳化后，也没有明显的形态变化。拉曼散射研究表明，碳化样品的石墨化程度和石墨微晶域尺寸取决于苯酚含量。碳材料表现出最高比表面积为579 m²/g以及孔体积为0.398 cc/g，这一观察结果表明所制备的碳是多孔的。我们的研究结果说明了一种简便有效的策略来制备多种碳形态，这些碳形态可作为储能应用的潜在候选材料。
