APPLICATION TO CLASSROOM

125

Ppy has a range of properties caused by several factors such as how the cross-linking structures between polymer chains were formed and interspersed with the charged-balancing anions of surfactants, under what conditions polymerization was carried out such as electrolyte concentration, temperature, type of dopants, power supply, oxidation degree of the Ppy. etc. Chemical reaction mechanism, properties and fundamental applications of Ppy have also been discussed in detail in other publications (McNeill, 1963; Street, 1983; Kang, 2000;

RHEE, 1989; Kupila, 1993; Kakouris, 1992; Saville, 2005; Steven, 1993; Buting, 1997, Morales, 2000; Puanglek, 2012; Leonavicius, 2011)

VI. APPLICATION TO CLASSROOM

126

one another the films they produced amongst the groups. All groups of the students had opportunity to observe and to measure the conductivity of the six types of the films. All the sample solutions and materials were prepared for the students before the class periods. The students got similar results to those shown in Table 5-3.

2. Evaluation of the developed teaching and learning materials

<In General>

It was interesting that, in response to questions in the lesson introduction, all students replied with strong confidence that no plastic or polymer could conduct electricity. This was the most important part of the lesson and was intended to 'hook' the students' interest and motivate them towards a scientific and skilled investigation. During the investigation, the students were surprised that the Ppy polymer films were easily generated by electropolymerization and that they could conduct electricity. Beyond this, the students also observed that the Ppy films could be doped very well by some surfactants. The results showed that the surfactants containing the sulfonate group (SO3

) in the molecule seemed to dope the Ppy films more easily than those containing the carboxylate group (COO^). During discussion the students understood that sulfonate surfactants might form micelles better than carboxylate surfactants by entrapping pyrrole molecules as monomers in the electrolyzed solution.

The students also found that among the conductive polymers, there was a variety of electrical conductivity. Through group discussion, the students found out which factors caused Ppy films to have different conductivity, such as type of surfactant, duration of electrolysis, distance between electrolyte electrodes, electrolyte concentration, power supply and so on. Therefore, the lessons provided students with an opportunity to study current science and technology about conductive plastics,which are being using commonly in daily life.

127

<Knowledge Improvement>

In general, the lessons could provide several scientific l knowledge and skills to the students. As seen in Fig. 5-10, may students responded in the questionnaires to evaluate their own understanding that they understood the lesson concepts they learned from the lessons very well. This feedback was corresponding to their performance on the post test compared to that of pre-test, in which most of the students could achieve high scores (Fig. 5-11).

Moreover, the students also commented that they learned a lot of knowledge and skills during the lesson as shown in Fig. 5-12.

Fig. 5-10. Students evaluated their understanding on the lessons

Fig. 5-11. Students’ achievement on pre/post tests

Note: The detail questions on pre/post tests are attached in the APPENDIX

Clear understood

0%

Understood 60%

Somehow understood

40%

Did not understand

at all 0%

0 1 2 3 4 5 6 7 8 9 10

Q1: Ppy Properties Q2: Method to measure a material conductivity like Ppy.

Number of responses

Pre-test Post-test

128

Fig. 5-12. Knowledge and skills students learned from the lessons

<Applicability>

Fir. 5-13. Extent of applicability by using the hand-made apparatus

Most students could participate well with the lesson activities smoothly, as well as handle with the developed teaching and learning apparatus. They responded that although the developed materials seemed a bit difficult for them to understand its principle concept, they could operate to obtain the results from the experiments very well. As seen in

0 10 20 30 40 50 60 70 80 90 Ppy can conduct electricity

SNS is the best to make conductive Ppy Sulfonate anion could produce Ppy much

better than carboxyl anion How to calculate conductivity of Ppy

Ppy can be produced by electrolysis The distance between electrodes affects Ppy

properties

Number of responses (%)

Very Easy 0%

Easy 10%

Not too easy, but

feasible 90%

Very Difficult 0%

129

Fig. 5-13, most of them chose “Not too easy, but feasible” responding in the questionnaires.

That means, the developed apparatus can be used properly by the students in the real classroom to investigate the conductive property of the semiconductor thin film such as pi.

<Students’ Satisfaction>

Although the lesson seemed a bit difficult to the students due to the contents on polypyrrole polymer was new to them, the students still showed high satisfaction on the lessons activities and the teaching materials were introduced in the lessons. As shown in the Fig. 5-14, many of them responded “Satisfied” and no one chose “Did not satisfied at all”.

This result was also corresponded to the students‟ interests in each lesson topic as shown in Fig. 5-15. Most them were surprised when the lessons showed that the plastic of polypyrrole they made could conduct electricity, which they have never realized before. Therefore, this lesson could hook the students‟ interest effectively in further scientific investigation as a basic demand of science lessons.

Fig. 5-14. Extent of students‟ satisfaction on the lessons activities and teaching materials

Much satisfied 20%

Satisfied 70%

Little satisfied 10%

Did not satisfied at all

0%

130

Fig.5-15. The interesting concepts/activities for students.