Improvement of Polystyrene Nano-Spheres Density and Uniformity of Mechanical Organization on PDMS Substrates Lotem Kitaroo and Sharon Luzky
The system being analyzed in the solution is focused on the mechanical organization and distribution of polystyrene nanospheres with varying sizes on a polydimethylsiloxane (PDMS) substrate using a mechanical rubbing process.
The main components and processes of the system include:
1. Polystyrene Nanospheres-
Materials: Polystyrene nanospheres with specific diameters (e.g., 0.35 µm and 0.5 µm).
Preparation: The nanospheres are prepared in dry powder form by mixing solutions of different sizes, centrifuging to remove liquid, and drying the resultant powder.
2. Polydimethylsiloxane (PDMS) Substrate-
Materials: Silicone elastomer base mixed with a cross-linker.
Preparation: The mixture is degassed under vacuum and cured at 60°C to form a solid elastomeric material. PDMS pieces are cut to fit into the rubbing machine and to match the size of the model holders.
3. Rubbing Process-
Polystyrene powder is sprinkled onto the PDMS substrate.
Smaller PDMS circles (1” diameter) are attached to the model holders, and a larger PDMS piece (8” diameter) is placed on the stage of the rubbing machine.
The rubbing machine operates at 30 RPM, with experiments conducted for different durations (e.g., 6 minutes and 25 minutes).
The machine combines rotational and translational motion to ensure uniform rubbing and avoid the formation of a second layer.
4. SEM Imaging-
Samples are placed in the SEM chamber.
High-resolution images are captured to assess nanosphere distribution, arrangement, and uniformity.
5. Image Analysis using OpenCV-
Detects circular features representing nanospheres.
Differentiates between large and small nanospheres based on radii.
Identifies clusters and calculates statistical metrics such as cluster size and distribution patterns.
2
0
Process Overview-
- Objective: Achieve a dense and uniform layer of polystyrene nanospheres on PDMS substrates.
- Steps: Mechanical rubbing of PDMS, sputtering with nanospheres, SEM imaging, and image analysis.
Problem Statement-
Despite systematic processing, SEM images show sparse and uneven distribution of nanospheres.
Mechanical Rubbing of PDMS
OE 3.6
Sputtering with Polystyrene Nanospheres.
OE 2.5
SEM Imaging of Samples and Image Processing and Analysis
OE 1
Productive operations effectiveness
Effective
Ineffective
Operation types breakdown
Productive
Providing
Corrective
Metrology
| Operation Type | Does it increase cost? | Does it increase product value? | Recommendation |
|---|---|---|---|
Productive | Yes | Yes | Improve |
Providing | Yes | No | Eliminate |
Corrective | Yes | No | Eliminate |
Metrology | Yes | No | Eliminate |
| Operation | Type | Merit | Recommendation |
|---|---|---|---|
| Mechanical Rubbing of PDMS | Productive | OE 3.6 | Consider improving |
| Sputtering with Polystyrene Nanospheres. | Providing | OE 2.5 | Consider eliminating |
| SEM Imaging of Samples and Image Processing and Analysis | Metrology | OE 1 | Consider the necessity of the information and eliminate it when possible |
Improve the surface preparation of PDMS to achieve a dense and uniform layer of polystyrene nanospheres.
Operational Effectiveness – OE
Effective
Ineffective
OE 3.6
Operational Perfectness - OP
Basic functions
Components
Supersystems
OP 0.4
Big nanospheres | 10 1.5 |
Small nanospheres | 10 1.5 |
rubbing tool | 6.7 |
Sample holder | 6.7 |
PDMS substrate | 6.7 |
Gear | 6.7 10 |
To reduce the influence of the supersystem and of harmful relationships and to maximize the influence of contributing relationships.
The system aims to achieve a uniformly coated PDMS substrate with polystyrene nanospheres through a sputtering process. This process involves several components and subsystems that work together to deposit nanospheres onto the PDMS substrate uniformly. The primary product of this system is a PDMS substrate that is densely and uniformly coated with polystyrene nanospheres, suitable for applications in nanoelectronics, biomedical devices, and surface coatings.
Operational Effectiveness – OE
Effective
Ineffective
OE 2.5
Operational Perfectness - OP
Basic functions
Components
Supersystems
OP 0.09
PDMS Substrate | 10 |
Polystyrene Nanospheres
| 10 10 |
Substrate Holder
| 6 |
Target Material Holder
| 6 |
Sputtering Equipment
| 6 6 |
Rotating Mechanism
| 4 4 |
Power Supply
| 4 |
Control System
| 4 |
Cooling System
| 4 |
Vacuum Chamber
| 4 4 |
Environmental Conditions
| 2 |
Ensure maintenance, electrical system and correct parameters in the sputtering system.
SEM Imaging of Samples. - The system involves imaging polystyrene nanospheres deposited on PDMS substrates using SEM.
Operational Effectiveness – OE
Effective
Ineffective
OE 1
Operational Perfectness - OP
Basic functions
Components
Supersystems
image processing software | 10 10 |
Algorithms | 5 |
Hardware | 5 |
operator | 10 |
SEM device | No impact |
PDMS samples with nanospheres | No impact |
Calibration: Regular calibration of the SEM Device.
Training: Enhanced training for operators.
Software Updates: Regular updates and testing of Image Processing Software.
Environmental Control: Maintain optimal room conditions for SEM imaging.
If | Gear remains unchanged |
|---|---|
Then | Gear Moves Big and small nanospheres and make them connect |
But | Gear Separates Big and small nanospheres |
SEM images reveal that the nanospheres are sparsely distributed with noticeable gaps between them.
Explore alternative deposition techniques such as drop-casting or inkjet printing to achieve a more uniform arrangement of the nanospheres on the substrate.
3
Sputtering method being used may not be suitable for achieving dense packing of polystyrene nanospheres.
Investigate and implement a different sputtering method that is known to be more effective for achieving dense packing of polystyrene nanospheres.
2
sputtering can cause issues like non-uniform distribution and potential shrinkage of the nanospheres.
Utilize a different deposition technique, such as spin coating, to achieve a more consistent and even layer of nanospheres.
1
The energy and dynamics involved in the sputtering process may not be appropriate for depositing delicate materials like polystyrene nanospheres, leading to uneven deposition and structural changes.
Implement a pre-treatment step for the substrate to enhance adhesion and uniformity of deposition.
0
Insufficient research or testing on the compatibility of sputtering process with polystyrene nanospheres
Conduct thorough research and testing specifically focused on the compatibility of sputtering process with polystyrene nanospheres
4
Anatoly Agulyansky
It is a great job, guys. You analyzed the problem. used creative thinking tools, generated innovative ideas and tested them.
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