当前位置: X-MOL 学术Langmuir › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Probing Single-Molecule Adhesion of a Stimuli Responsive Oligo(ethylene glycol) Methacrylate Copolymer on a Molecularly Smooth Hydrophobic MoS2 Basal Plane Surface
Langmuir ( IF 3.7 ) Pub Date : 2017-09-25 00:00:00 , DOI: 10.1021/acs.langmuir.7b01187
Yuechao Tang 1 , Xurui Zhang 1 , Phillip Choi 1 , Qingxia Liu 1 , Zhenghe Xu 1
Affiliation  

Molybdenum disulfide (MoS2) has been receiving increasing attention in scientific research due to its unique properties. Up to now, several techniques have been developed to prepare exfoliated nanosize MoS2 dispersions to facilitate its applications. To improve its desired performance, as-prepared MoS2 dispersion needs further appropriate modification by polymers. Thus, understanding polymer–MoS2 interaction is of great scientific importance and practical interest. Here, we report our results on molecular interactions of a biocompatible stimuli-responsive copolymer with the basal plane surface of MoS2 determined using single molecule force spectroscopy (SMFS). Under isothermal conditions, the single-molecule adhesion force of oligo(ethylene glycol) methacrylate copolymer was found to increase from 50 to 75 pN with increasing NaCl concentration from 1 mM to 2 M, as a result of increasing hydrophobicity of the polymers. The theoretical analysis demonstrated that single-molecule adhesion force is determined by two contributions: the adhesion energy per monomer and the entropic free energy of the stretched polymer chain. Further data analysis revealed a significant increase in the adhesion energy per monomer with a negligible change in the other contribution with increasing salt concentration. The hydrophobic attraction (HA) was found to be the main contribution for the higher adhesion energy in electrolyte solutions of higher NaCl concentrations where the zero-frequency of van der Waals interaction were effectively screened. The results illustrate that oligo(ethylene glycol) methacrylate copolymer is a promising polymer for functionalizing MoS2 and that one can simply change the salt concentration to modulate the single-molecule interactions for desired applications.

中文翻译:

在分子光滑的疏水性MoS 2基平面表面上探测刺激性低聚(乙二醇)甲基丙烯酸甲酯共​​聚物的单分子粘附性。

由于其独特的特性,二硫化钼(MoS 2)在科学研究中受到越来越多的关注。迄今为止,已经开发了几种技术来制备剥落的纳米级MoS 2分散体,以促进其应用。为了改善其期望的性能,所制备的MoS 2分散体需要通过聚合物进一步适当的改性。因此,了解聚合物与MoS 2的相互作用具有重大的科学意义和实际意义。在这里,我们报告我们的结果与生物相容性刺激响应共聚物与MoS 2的基面表面的分子相互作用。使用单分子力光谱法(SMFS)测定。在等温条件下,由于聚合物疏水性的增加,发现随着NaCl浓度从1 mM增至2 M,低聚(乙二醇)甲基丙烯酸乙二醇酯共聚物的单分子粘附力从50 pN增至75 pN。理论分析表明,单分子粘附力由两个因素决定:每个单体的粘附能和拉伸的聚合物链的熵自由能。进一步的数据分析表明,随着盐浓度的增加,每个单体的粘附能显着增加,而其他贡献的变化可忽略不计。已发现疏水吸引力(HA)是在较高NaCl浓度的电解质溶液中较高粘附能的主要贡献,其中有效筛选了范德华相互作用的零频率。结果表明,低聚(乙二醇)甲基丙烯酸甲酯共​​聚物是用于功能化MoS的有前途的聚合物2可以简单地改变盐浓度来调节单分子相互作用,以实现所需的应用。
更新日期:2017-09-25
down
wechat
bug