Vacuum Fluid Sampler Pillar-Supported Membrane Design
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Solution Overview
Problem
Conventional liquid cells for transmission electron microscopy (TEM) face challenges in maintaining a uniform and thin liquid layer, controlling fluid flows, and withstanding high pressures, which limits high-resolution imaging and spectroscopy, especially in liquid environments.
Innovation Solution
A monolithic liquid cell design with pillar-supported, SiN membranes and a sacrificial chromium oxide layer, allowing for precise control of liquid thickness and pressure resistance, enabling high-resolution imaging and spectroscopy by eliminating spacers and membrane bulging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional liquid cells are used for TEM imaging, then fluid sampling is possible, but uniform and thin liquid layer control is poor
Solution Approach 1:
The liquid cell is segmented into distinct functional regions: a support structure with regularly spaced pillars, thin membrane layers spanning between pillars, and fluid flow channels. This segmentation allows independent optimization of each component - pillars provide mechanical support while membranes maintain uniform liquid thickness, resolving the contradiction between structural simplicity and liquid layer uniformity.
Solution Approach 2:
The support structure with pillars and membranes is pre-assembled and sealed before fluid introduction. This preliminary action establishes the uniform liquid layer geometry in advance, ensuring that when fluid is introduced, it automatically conforms to the pre-defined uniform thickness between membranes, achieving precise liquid layer control without complex real-time adjustments.
2Stress or pressure
If conventional liquid cells are used, then imaging is possible, but pressure withstanding capability is limited
Solution Approach 1:
The cell structure employs local quality differentiation: rigid support pillars provide mechanical strength and pressure resistance at critical support points, while thin flexible membranes maintain liquid layer uniformity in the fluid containment regions. This localized functional assignment allows the structure to withstand high pressures while preserving liquid layer uniformity, as each component operates in its optimal performance regime.
3Measurement precision
If conventional liquid cells are used, then fluid containment is possible, but high-resolution spectroscopy is limited
Solution Approach 1:
The liquid is enclosed between extremely thin membrane films that minimize scattering and absorption of electron beams. These thin film membranes provide sufficient mechanical containment while being sufficiently transparent to electron transmission, thereby improving signal-to-noise ratio and enabling high-resolution spectroscopy without compromising fluid containment integrity.
4Manufacturing precision
If spacers are used to maintain membrane separation, then liquid layer thickness is controlled, but imaging resolution is reduced due to bulging
Solution Approach 1:
The design extracts and eliminates the problematic spacer components from the liquid cell structure. Instead of using spacers that create local thickness variations and membrane bulging, the invention uses a pillar-supported membrane architecture where membranes span between rigid pillars without requiring spacers, thereby achieving uniform liquid layer thickness control while maintaining imaging resolution free from bulging artifacts.
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 design achieves atomic-scale imaging and quantitative electron energy-loss spectroscopy with improved signal-to-noise ratio and pressure tolerance, overcoming limitations of conventional liquid cells.
Implementation Method 1
contacting the sacrificial member with an etchant, the etchant being selective to etch chromium oxide and substantially inert with respect to etching the composite structure; and selectively etching the sacrificial member by the etchant to selectively remove the sacrificial member from the composite structure
Data Source
AI summary
A fluid sampler includes: a sample cell that includes: a substrate comprising: a first port; a second port in fluid communication with the first port; a viewing reservoir in fluid communication with the first port and the second port and that receives the fluid from the first port and communicates the fluid to the second port, the viewing reservoir including: a first view membrane; a second view membrane; and a pillar interposed between the first view membrane and second view membrane, the pillar separating the first view membrane from the second view membrane at a substantially constant separation distance such that a volume of the viewing reservoir is substantially constant and invariable with respect to a temperature and invariable with respect to a pressure to which the sample cell is subjected.