单壁碳纳米管的溶解,通过螺旋式粉素的超分子封装
Oh-Kil Kim1, Jongtae Je, Jeffrey W Baldwin
1Chemistry Division, Naval Research Laboratory, Washington, DC 20375-5342, USA. okkim@ccs.nrl.navy.mil
Journal of the American Chemical Society
|April 10, 2003
概括
研究人员创建了一种简单的方法,使用粉素在DMSO/水中溶解单壁碳纳米管 (SWNT). 这一过程有效地分离SWNT捆并使完全溶解,而不需要特定的粉状结构.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
- 生物化学 生物化学
背景情况:
- 单壁碳纳米管 (SWNTs) 由于强大的管间范德瓦尔斯力,难以溶解,限制了它们的应用.
- 开发有效的溶解方法对于在各种领域利用SWNT特性至关重要.
研究的目的:
- 建立一个简单而高效的过程,用于单壁碳纳米管 (SWNTs) 的水溶化,使用粉.
- 调查SWNT-粉素相互作用和溶解的最佳条件.
主要方法:
- 对SWNT进行预声波,以分离捆绑.
- 在优化水性二甲基硫氧化物 (DMSO) 混合物 (10-20% DMSO) 中用粉素进行处理.
- 使用扫描电子显微镜 (SEM) 和原子力显微镜 (AFM) 进行溶解SWNT的表征.
主要成果:
- 实现了SWNTs的即时和完全溶解.
- 确定了最佳的DMSO/H2O混合物 (10-20% DMSO) 以最大限度地实现SWNT与氨酸的相互作用.
- 观察到氨酸不需要螺旋形状的SWNT封装.
- SEM和AFM发现松散扭曲的粉丝丝带包裹SWNTs没有凝结.
结论:
- 已经开发出一种简单有效的SWNT溶解方法,在水性DMSO中使用粉素.
- 该过程是高效的,不需要预先形成的粉素螺旋,扩大了其适用性.
- 这些发现促进了SWNT在基于解决方案的应用中通过克服分散挑战来使用SWNT.
相关概念视频
02:06Newman Projections
Different notations are used to represent the three-dimensional structure of molecules on two-dimensional surfaces. One of the most commonly used representations is the dash-wedge formula. The dashed wedges, solid wedges, and the plane lines indicate the groups situated behind the plane, coming out of the plane, and in the plane, respectively.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.
01:13¹H NMR: Complex Splitting
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
01:28Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
01:04¹³C NMR: ¹H–¹³C Decoupling
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
01:12Double Resonance Techniques: Overview
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...