Binding Affinities and Thermodynamics of Noncovalent Functionalization of Carbon Nanotubes with Surfactants
Binding Affinities and Thermodynamics of Noncovalent Functionalization of Carbon Nanotubes with Surfactants
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DOI：
10.1021/la4022933
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发表时间：
2013-09-01
期刊：
影响因子：
3.9
通讯作者：
Ju, Sang-Yong
中科院分区：
文献类型：
--
作者：
Oh, Hyunkyu;Sim, Jinsook;Ju, Sang-Yong
表面活性剂和碳纳米管之间的结合亲和力和热力学理解对于开发各种碳纳米管应用至关重要。黄素单核苷酸包裹的碳纳米管在光学特征上表现出较大的红移，用于测定 12 种不同纳米管手性与其他表面活性剂交换后的结合亲和力和相关热力学参数。从 S 形转变的中点确定平衡常数 (K)，它与初始表面活性剂-碳纳米管的结合亲和力成反比，提供了表面活性剂的定量结合强度，因为 SDBS > SC 近似于 FMN > SDS，而与 SWNT 的电子类型无关。金属管的结合亲和力比半导体管的结合亲和力弱。半导体管的复杂 K 模式显示出对某些 SWNT 手性的偏好，以及根据纳米管手性的表面活性剂特异性协同性。控制温度可以有效地将 K 值调节 30%，并使我们能够探测热力学参数。等号的焓变和熵变会产生几 kJ/mol 量级的吉布斯能量变化。表面活性剂交换时更大的负吉布斯能量会产生增强的纳米管光致发光，这意味着了解热力学对于设计纳米管分离和表面活性剂的超分子组装的重要性。
Binding affinity and thermodynamic understanding between a surfactant and carbon nanotube is essential to develop various carbon nanotube applications. Flavin mononucleotide-wrapped carbon nanotubes showing a large redshift in optical signature were utilized to determine the binding affinity and related thermodynamic parameters of 12 different nanotube chiralities upon exchange with other surfactants. Determined from the midpoint of sigmoidal transition the equilibrium constant (K), which is inversely proportional to the,binding affinity of the initial surfactant-carbon nanotube, provided quantitative binding strengths of surfactants as SDBS > SC approximate to FMN > SDS, irrespective of electronic types of SWNTs. Binding affinity of metallic tubes is weaker than that of semiconducting tubes. The complex K patterns from semiconducting tubes show preference to certain SWNT chiralities and, surfactant-specific cooperativity according to nanotube chirality. Controlling temperature was effective to modulate K values by 30% and enables us to probe thermodynamic parameters. Equally signed enthalpy and entropy changes produce Gibbs energy changes with a magnitude of a few kJ/mol. A greater negative Gibbs energy upon exchange of surfactant produces an enhanced nanotube photoluminescence, implying the importance of understanding thermodynamics for designing nanotube separation and supramolecular assembly of surfactant.