Project Details

Organisation:	IMRE, A*STAR
Mentor:	Dr Mya Khine Yi
Members:	Zenia and Eastina =)
Project Title:	Preparation and Characterisation of Ultra- Thin Multi layer films using self assembly spin method

A. Brief Description of Project
The main purpose of this project is supposed to be to for us to learn to form ultra-thin multi layers on a substrate. The ultra-thin multi layers are formed from depositing two different chemicals by alternating them and using the spin coater. This would then create a hydrophobic or hyrophilic layer on the substrate depending on which chemical we end off with (odd or even number of layers). After depositing each layer, the film is washed twice with water and dried with a hot plate at 100 degree Celsius to ensure that all the unreacted chemical and water does not stay on the substrate.

- The two chemicals used are Poly(poly 4-styrene sulfonate) (POSS) and Octa ammonium polyhedralogligomeric silsesquioxane (OAP).

To determine the hydrophobicity or hydrophilicity of the multi layer film on the substrate, the water contact angle method is used. It is the process of using a machine to drop a very tiny water droplet on the multi layered film. The more the water droplet spreads out and becomes flat, the more hydrophilic the film is. So vice versa, the more rounded the water droplet is, the more hydrophobic the film is. The water contact angle is determined by measuring the angles at the two ends of the water droplet using a machine.

The thickness of the multi layered film is also measured using the Surface Profiler Machine. Since the number of layers that we have deposited on our substrate is not many, we have to use a penknife to create a trench in the film so the machine can measure the height or thickness of the film deposited. The machine is only valid for substrates with 30 layers and above.

B. Results
Conclusion: OAP is more hydrophobic.

No. of layers	Try no.	Left	Right	Mean
1	1	50.8	58.5	54.7
1	2	54.6	54.4	54.5
2	1	68.5	71.0	69.8
2	2	68.2	70.6	69.4
2	3	67.5	66.0	66.8
3	1	57.3	54.6	55.9
3	2	53.0	56.3	54.6
3	3	64.3	66.9	65.6
4	1	62.1	62.4	62.2
4	2	60.7	62.4	62.2
4	3	53.3	52.1	52.7
5	1	58.6	61.3	60.0
5	2	66.1	67.1	66.6
5	3	73.2	70.1	71.6
5	4	62.0	62.0	62.0

6	1	65.6	71.2	68.4
6	2	77.5	74.5	76.0
6	3	73.7	71.5	72.6
7	1	33.7	35.1	34.4
7	2	28.5	24.5	26.5
7	3	18.3	22.1	20.2
7	4	20.5	21.5	21.0
7	5	24.2	25.1	24.7
7	6	32.7	31.9	32.3
7	7	30.6	28.7	29.6
9	1	44.6	47.4	46.0
9	2	45.3	39.0	42.1
9	3	52.7	38.5	45.6
9	4	25.5	25.0	25.2
9	5	26.5	25.5	26.0
11	1	20.9	18.8	19.9
11	2	23.3	18.2	20.7
20	1	63.1	61.4	62.2
20	2	62.8	63.8	63.3
20	3	60.0	60.5	60.3
21	1	25.9	25.5	25.7
21	2	24.9	26.9	25.9
30	1	17.7	24.8	21.2
30	2	19.7	21.1	19.9
40	1	52.6	53.6	53.1
40	2	52.7	52.5	52.6
45	1	33.2	33.1	33.4
45	2	28.1	28.0	28.1
50	1	49.4	49.9	49.6
50	2	49.7	49.7	49.7

C. Reflection

Three content knowledge/skills that we have learnt

1. Determining hydophobicity and hydrophilicity of a surface
2. Many dangers of chemicals, their categories and character
3. The Young Equation


Two interesting aspects about our learning

1. We had to dress up from top to bottom everyday when we went into cleanrooms
2. There are a few machines that many people vie for and have to actually queue to use

One take-away for life

1. Nothing beats experience.

Gallery

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