ABSTRACT The functionalisation of carbon nanotubes (CNTs) with biomolecules in an aqueous environment has found considerable potential applications in nanobiotechnology. To understand the structural properties under physical adsorption and mechanical characteristics of non-covalently functionalised CNTs with four important biomolecules in aqueous environment, i.e. l-alanine, guanine, thymine and uracil, molecular dynamics (MD) simulations are performed. It is demonstrated that, unlike l-alanine, the main factor of adsorption is Π-Π stacking together with van der Waals (vdW) interactions. Computation of gyration radius reveals that gyration radius increases linearly as the weight percentage of functional biomolecules increases. Also, it is shown that the presence of water molecules leads to more expansion of biomolecules around CNTs. Simulations show that Young’s modulus of the adsorbed CNTs is slightly smaller than that of pure ones. Furthermore, it is demonstrated that the critical buckling force of functionalised CNT is higher than that of pure CNT. Also, for high aspect ratios, the critical strain of functionalised CNTs is found to be lower than that of pure ones and changes linearly by increasing the weight percentage of functional biomolecules. The buckling modes of functionalised CNTs in vacuum and aqueous environments are explored.

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基于分子动力学模拟的水环境中生物分子物理吸附下碳纳米管的吸附分析及力学特性

摘要 碳纳米管 (CNT) 在水性环境中与生物分子的功能化已在纳米生物技术中发现了相当大的潜在应用。为了了解在水性环境中具有四种重要生物分子（即 l-丙氨酸、鸟嘌呤、胸腺嘧啶和尿嘧啶）的非共价官能化碳纳米管在物理吸附下的结构特性和机械特性，进行了分子动力学 (MD) 模拟。已证明，与 l-丙氨酸不同，吸附的主要因素是 Π-Π 与范德华 (vdW) 相互作用叠加在一起。回转半径的计算表明回转半径随着功能生物分子重量百分比的增加而线性增加。此外，还表明水分子的存在会导致碳纳米管周围生物分子的更多膨胀。模拟表明，吸附的碳纳米管的杨氏模量略小于纯碳纳米管的杨氏模量。此外，还表明功能化碳纳米管的临界屈曲力高于纯碳纳米管的临界屈曲力。此外，对于高纵横比，功能化碳纳米管的临界应变低于纯碳纳米管的临界应变，并通过增加功能生物分子的重量百分比而线性变化。探索了真空和水性环境中功能化碳纳米管的屈曲模式。发现功能化碳纳米管的临界应变低于纯碳纳米管的临界应变，并且通过增加功能生物分子的重量百分比而线性变化。探索了真空和水性环境中功能化碳纳米管的屈曲模式。发现功能化碳纳米管的临界应变低于纯碳纳米管的临界应变，并且通过增加功能生物分子的重量百分比而线性变化。探索了真空和水性环境中功能化碳纳米管的屈曲模式。