Diamond Nanopowder Gravimetric Sensor Uniform Deposition
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Solution Overview
Problem
Existing gravimetric chemical or biochemical sensors of the acoustic resonator type face challenges in achieving uniform and reproducible sensitive layer deposition, leading to inaccurate measurements due to variations in acoustic properties and limited selectivity, especially with polymers, molecularly imprinted polymers, metal complexes, and carbon nanotubes.
Innovation Solution
A gravimetric sensor using a nanometric diamond powder as the sensitive layer, which forms a three-dimensional stack on the transducer, allowing for uniform deposition and high selectivity through functionalization with molecules like porphyrins or phthalocyanines, enhancing sensitivity and reducing interference from acoustic property variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional deposition methods (vaporization, spinner deposition, drop deposition) are used to form sensitive layers, then ease of manufacture is improved, but manufacturing precision deteriorates due to insufficient reproducibility and uniformity
Solution Approach 1:
The patent uses nanoporous anodic aluminum oxide (AAO) templates to guide the formation of sensitive layer structures. The porous architecture of AAO provides standardized channels that ensure uniform distribution and consistent morphology of the sensitive material throughout the layer, resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent systematically controls deposition parameters including template pore size (20-200 nm), deposition temperature, and material concentration to achieve reproducible sensitive layers. By optimizing these parameters within specific ranges, the method attains both ease of manufacture through simple deposition processes and high manufacturing precision through controlled structural formation.
2Adaptability or versatility
If molecularly imprinted polymers are used to increase selectivity, then selectivity is improved, but device complexity increases due to the need for large quantities of polymer and complex imprinting processes
Solution Approach 1:
The patent segments the sensitive layer into discrete nanoscale units formed within individual pores of the AAO template. Each pore contains a separate sensitive material structure, creating numerous independent recognition sites throughout the layer. This segmentation achieves high selectivity through cumulative effect of many small units rather than requiring large quantities of complex imprinted polymer.
Solution Approach 2:
The porous AAO template provides a pre-formed nanostructured architecture that simplifies the creation of selective recognition sites. The uniform pore structure eliminates the need for complex polymer imprinting processes by providing standardized cavities that can be filled with selective materials, reducing device complexity while maintaining high selectivity.
3Adaptability or versatility
If metal complexes of macrocycles are used as adsorbent materials, then selectivity is improved, but response time worsens due to compact film morphology and low diffusion coefficients
Solution Approach 1:
The patent employs porous AAO templates to create a highly porous sensitive layer structure with interconnected channels. This porous architecture provides excellent mass transport pathways that enable rapid diffusion of target molecules throughout the sensitive layer, achieving fast response times while maintaining the chemical selectivity of metal complex materials.
Solution Approach 2:
The patent transitions from two-dimensional compact films to three-dimensional porous structures by utilizing the vertical dimension of the AAO template pores. This dimensional change creates open pathways for rapid molecular transport while providing sufficient volume for selective metal complex interactions, simultaneously improving response speed and maintaining selectivity.
4Quantity of substance
If carbon nanotubes are used as adsorbent materials, then sensitivity is improved due to high surface/volume ratio, but manufacturing precision deteriorates due to difficulty in obtaining uniform and reproducible deposition
Solution Approach 1:
The patent uses porous AAO templates to confine carbon nanotube deposition within standardized pore channels. This confinement ensures uniform distribution of nanotubes throughout the sensitive layer, with each pore containing a controlled amount of material. The template structure guarantees reproducible morphology and consistent surface area across all sensors, resolving the manufacturing precision issues associated with free-standing nanotube deposition.
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 diamond nano-powder-based sensor achieves improved reproducibility, sensitivity, and selectivity, with reduced interference from acoustic property variations, enabling effective detection of various chemical and biochemical species while maintaining long-term stability.
Implementation Method 1
a sensitive layer capable of adsorbing one or more specific chemical or biochemical species
Implementation Method 2
the measurement of a variation in the resonance frequency of the sensor
Implementation Method 3
a gravimetric transducer of the acoustic resonator type (also called an acoustic transducer, for example a piezoelectric transducer)
Data Source
Figure 1~2
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Figure 5~6
AI summary
The invention relates to a gravimetric chemical or biochemical sensor of the acoustic resonator type (200), and to a method for making same. The chemical or biochemical sensor includes: a gravimetric transducer of the acoustic resonator type (100); a so-called sensitive layer (10) capable of adsorbing one or more predetermined chemical or biochemical species, said sensitive layer being formed on a surface of the gravimetric transducer of the acoustic-resonator type (100), characterised in that the sensitive layer (10) contains a diamond powder having nanometric-sized grains (1).