Carbon Nanotube TEM Grids With Hydrogen-Assisted Infiltration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Carbon nanotube forests delaminate upon cooling after additional carbon infiltration, and existing TEM grids made of high-Z metals or expensive, toxic materials like copper, beryllium, or diamond are unsuitable for chemical and biological applications, leading to inaccurate EDXS analysis and structural limitations.
Innovation Solution
Infiltrate carbon nanotubes with carbon using hydrogen during the infiltration process to prevent delamination and create TEM grids composed of low-Z carbon materials, such as boron carbide, alumina, or silicon dioxide, which are chemically resistant and avoid high-Z atom interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If additional carbon is added to the carbon nanotube forest via chemical deposition, then the carbon content increases, but the nanotubes delaminate from the substrate upon cooling
Solution Approach 1:
Hydrogen gas is introduced as an intermediary substance during the carbon infiltration process. The hydrogen atmosphere acts as a mediator that prevents delamination by maintaining thermal stress balance during cooling, allowing carbon to be deposited without compromising substrate adhesion
Solution Approach 2:
The chemical composition of the infiltration atmosphere is changed from pure carbon-source gas to a mixture containing hydrogen. This parameter change in the gas composition enables carbon deposition while preventing the thermal stress-induced delamination that occurs with conventional carbon infiltration methods
2Strength
If high-Z metal grids are used for TEM support, then structural strength is provided, but EDXS analysis shows unwanted interference from the support structure
Solution Approach 1:
The high-Z metal support structure is completely removed and replaced with a low-Z carbon nanotube forest structure. This extraction of the problematic metal component eliminates the source of EDXS interference while maintaining the necessary mechanical support function through the carbon nanotube architecture
Solution Approach 2:
The support structure is made homogeneous in terms of low atomic number materials. Both the support framework and the sample material are composed of low-Z elements (carbon, and potentially boron, nitrogen, or oxygen), creating material homogeneity that eliminates spectral interference in EDXS analysis
3Strength
If metal grids are used for chemical/biological applications, then structural support is provided, but metals react with samples or preparation materials
Solution Approach 1:
The carbon nanotube support structure serves as a disposable, chemically inert platform that can be used for various chemical and biological applications without contamination concerns. Unlike metals, the carbon structure does not react with samples or preparation chemicals, eliminating the need for extensive cleaning or replacement due to chemical degradation
4Manufacturing precision
If carbon nanotube forests are created on substrate, then the nanotube structure is formed, but additional carbon infiltration causes delamination upon cooling
Solution Approach 1:
Hydrogen gas serves as a protective intermediary during the carbon infiltration and subsequent cooling process. The hydrogen atmosphere mediates the thermal stress management, allowing the nanotube structure to be precisely formed and infiltrated with additional carbon while preventing delamination during the cooling phase
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces stable, high-strength, low-Z carbon TEM grids that resist bending and chemical reactions, allowing accurate EDXS analysis without metal interference, and enables scalable production of thin, suspended films for various applications.
Implementation Method 1
These materials generally are 'grown', via chemical deposition of carbon, upon a substrate
Implementation Method 2
If a researcher attempts to add additional quantities of carbon to the carbon nanotube forest (via a chemical deposition process involving ethylene within a heated furnace), the infiltrated carbon nanotubes will generally delaminate (separate) from the substrate upon cooling
Data Source
AI summary
Described herein are examples of systems, methods, apparatuses, and devices which include a carbon nanotube structure. The carbon nanotube structure may include a first carbon nanotube with a first top surface and a first bottom surface. The carbon nanotube structure may include a second carbon nanotube vertically aligned with the first carbon nanotube. The second carbon nanotube may include a second top surface and a second bottom surface. The first carbon nanotube and the second carbon nanotube may be infiltrated with carbon by a mixture that is flowing. The mixture may include a first amount of ethylene and a second amount of hydrogen. The carbon nanotube structure may include a thin film extending along the first bottom surface and the second bottom surface.