Department of Chemistry, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak, Malaysia.
Department of Chemistry, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak, Malaysia; Nanotechnology Research Centre, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, 35900 Tanjong Malim, Perak, Malaysia.
J Colloid Interface Sci. 2019 Jun 1;545:184-194. doi: 10.1016/j.jcis.2019.03.012. Epub 2019 Mar 6.
The compatibility of surfactants and graphene surfaces can be improved by increasing the number of aromatic groups in the surfactants. Including aniline in the structure may improve the compatibility between surfactant and graphene further still. Surfactants can be modified by incorporating aromatic groups in the hydrophobic chains or hydrophilic headgroups. Therefore, it is of interest to investigate the effects of employing anilinium based surfactants to disperse graphene nanoplatelets (GNPs) in natural rubber latex (NRL) for the fabrication of electrically conductive nanocomposites.
New graphene-philic surfactants carrying aromatic moieties in the hydrophilic headgroups and hydrophobic tails were synthesized by swapping the traditional sodium counterion with anilinium. H NMR spectroscopy was used to characterize the surfactants. These custom-made surfactants were used to assist the dispersion of GNPs in natural rubber latex matrices for the preparation of conductive nanocomposites. The properties of nanocomposites with the new anilinium surfactants were compared with commercial sodium surfactant sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and the previously synthesized aromatic tri-chain sodium surfactant TC3Ph3 (sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate). Structural properties of the nanocomposites were studied using Raman spectroscopy, field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). Electrical conductivity measurements and Zeta potential measurements were used to assess the relationships between total number of aromatic groups in the surfactant molecular structure and nanocomposite properties. The self-assembly structure of surfactants in aqueous systems and GNP dispersions was assessed using small-angle neutron scattering (SANS).
Among these different surfactants, the anilinium version of TC3Ph3 namely TC3Ph3-AN (anilinium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate) was shown to be highly efficient for dispersing GNPs in the NRL matrices, increasing electrical conductivity eleven orders of magnitude higher than the neat rubber latex. Comparisons between the sodium and anilinium surfactants show significant differences in the final properties of the nanocomposites. In general, the strategy of increasing the number of surfactant-borne aromatic groups by incorporating anilinium ions in surfactant headgroups appears to be effective.
通过增加表面活性剂中芳族基团的数量，可以提高表面活性剂与石墨烯表面的相容性。在结构中包含苯胺可能会进一步提高表面活性剂与石墨烯的相容性。可以通过在疏水链或亲水头基中引入芳族基团来修饰表面活性剂。因此，研究采用基于苯胺的表面活性剂在天然橡胶乳液 (NRL) 中分散石墨烯纳米片 (GNP) 以制备导电纳米复合材料的效果很有意义。
通过用苯胺取代传统的钠离子，合成了带有亲水头基和疏水尾中的芳族基团的新型亲石墨烯表面活性剂。使用 1 H NMR 光谱对表面活性剂进行了表征。这些定制的表面活性剂用于协助 GNP 在天然橡胶乳液基质中的分散，以制备导电纳米复合材料。用新型苯胺表面活性剂制备的纳米复合材料的性能与商业十二烷基硫酸钠 (SDS)、十二烷基苯磺酸钠 (SDBS) 和先前合成的芳族三链钠表面活性剂 TC3Ph3 (1,5-二氧代-1,5-双 (3-苯氧基 )-3-((3-苯氧基 )羰基 )戊烷-2-磺酸钠 ) 进行了比较。使用拉曼光谱、场发射扫描电子显微镜 (FESEM) 和高分辨率透射电子显微镜 (HRTEM) 研究了纳米复合材料的结构性能。使用电导率测量和 Zeta 电位测量评估表面活性剂分子结构中芳族基团总数与纳米复合材料性能之间的关系。使用小角中子散射 (SANS) 评估表面活性剂在水体系和 GNP 分散体中的自组装结构。
在这些不同的表面活性剂中，TC3Ph3 的苯胺版本即 TC3Ph3-AN（苯胺 1,5-二氧代-1,5-双 (3-苯氧基 )-3-((3-苯氧基 )羰基 )戊烷-2-磺酸钠）被证明在分散 NRL 基质中的 GNP 方面非常有效，使电导率比纯橡胶乳液提高了十一个数量级。对钠和苯胺表面活性剂的比较表明，纳米复合材料的最终性能存在显著差异。一般来说，通过在表面活性剂头基中引入苯胺离子来增加表面活性剂所携带的芳族基团的数量的策略似乎是有效的。
