実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）提出日 Date of Report

MLF Experimental Report

2016/3/28

課題番号 Project No.

装置責任者 Name of responsible person

2015A0217

Norifumi L. YAMADA

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）A neutron reflectometry study of polymer network structure at solid interface

SOFIA (BL-16)

実験責任者名 Name of principal investigator

実施日 Date of Experiment

Manabu INUTSUKA

2015/11/7 ~ 2015/11/10

所属 Affiliation
Kyushu university
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
In order to reveal the aggregation structure of polymer network near a solid interface, we have conducted neutronreflectivity to thin films of polyisoprene (PI, Figure 1) including photo-crosslink agents such as
trimethylolpropane tris(3-mercaptopropionate).

The films were prepared onto quartz substrates (60 mm × 60mm × 8 mm) by a spin-coating technique and then irradiated with UVlight to promote the cross-linking reactions.

After rinsing the films

with toluene to remove unreacted components, they were dried undervacuum at room temperature.

The film thickness was evaluated toFigure 1. Chemical structure of PI.

be 30 to 150 nm.

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

Neutron reflectivity (NR) curves of the sample films were collected in air as well as deuterated hexane(n-hexane-d14).

The measurements in air were performed by introducing neutron beams from the air side.

Inthe case of the experiments in n-hexane-d14, the sample film was placed in contact with n-hexane-d14 in a cell.
Then, neutron beams were conducted from the quartz side, as shown in Figure 2. Neutron beams with awavelength from 0.2 nm to 0.88 nm were used, and the incident angles  of 0.3, 0.75 and 1.8 deg. were chosen.
The films contacted with n-hexane-d14 for at least 12
hours prior to the measurements so that the films could
reach a quasi-equilibrium state.

quartz

By combining thePI

data sets acquired at different incident angles, NRn-hexane-d14

curve in the q range from 0.08 to 2 nm-1 was obtained.

neutronbeam

Figure 2. Schematic illustration of our sample cellfor NR measurements in d14-hexane.

The resolution of dq/q was about 0.03.

1

2. 実験方法及び結果（つづき） Experimental method and results (continued)
Panel (a) in Figure 3 shows the NR curves for a PI thin film in air and n-hexane-d14.
thin film in air exhibited Kiessig fringes corresponding tothe total film thickness.

On the other hand, the NR curve(a)Also, in the region higher than

0.4 nm1, the fringes were not clear.

These results makeit clear that the film was swollen by n-hexane-d14

Reflectivity

only in a low-q region.

interface. By fitting the NR curve by a layer model, we

air and n-hexane-d14, the mass conservation of PI was

210−2
10−4

10−8

computed the depth profile of (b/V) for the PI film
Both in1. air
2. n-hexane-d14

10−6accompanied with the film thickening and the diffusedsuccessfully, as shown in panel (b) of Figure 2.

1100for the PI film in n-hexane-d14 exhibited a narrower fringe

The NR curve for a PI

00.2

0.4

0.6

0.8

1.0

1.2q / nm−1(b)n-hexane-d14

cross-linked PI quartz

hold: the total mass of PI in both profiles was exactly theThe film thickness was estimated to7.0

be 44.0 nm by fitting the data with a simple 1-box model

6.0

with interfacial roughnesses.

The value was consistent

with that by X-ray reflectivity (XR) and ellipsometry
measurements.
Then, we tried to fit the NR curve for the PI film inn-hexane-d14 using a 3-layer model.

(b/V)∙104 / nm−2same for each other.

The best (b/V)

model is shown in panel (b) of Figure 2.

5.0
4.0
3.0
2.0

1.
2.

airn-hexane-d14

1.0

10

We also

2.5

confirmed that there is no reasonable profile with 1- and2-layers.

2

2.0

1.5

1.0

0.5

0h/hair

The cross-linked PI film was swollen byn-hexane-d14, and the total thickness increased from 44.0
to 71.4 nm.

The (b/V) value of the film also increased

due to the penetration of n-hexane-d14 into the network.
The swollen cross-linked PI film was divided into threelayers: well-swollen bulk layer, less-swollen intermediate
layer and not-swollen interfacial layer. The (b/V) valueof the interfacial layer is almost the same as that in theFigure 3. (a) Neutron reflectivity curves for across-linked PI film in air and n-hexane-d14,
respectively. Open symbols depict experimental
data and solid and dotted lines represent
reflectivity calculated on the basis of thescattering length density (b/V) profiles shown in(b).

bulkneat PI, meaning that this layer could be hardly swollen

looselyeven by a good solvent of PI, n-hexane-d14.

tightly

Moreover,the less-swollen intermediate layer was found between theinterfacial and bulk layers.

The average  in this layer

was calculated to be about 0.63.

We believe that these

two layers should correspond to “tightly” and “loosely”

substrate
Figure 4. Schematic illustration of the interfacial
structure with the adsorbed layers.

adsorbed layers historically discussed for the “bound rubber”. Our results will be published as the first paper
dealing with the detailed aggregation states of the polymer network near a solid interface.
2