THESIS
2006
xi, 72 leaves : ill. ; 30 cm
Abstract
In this thesis, the technique of FTIR and RDS were used to study the optical anisotropy of the rubbed PS thin films on SiO
2 substrate. The birefringence of PS with saturated rubbing was investigated. Generally, the birefringence of PS was come from two sources: segmental alignment and distortion. However, the distortion part could not be measured directly. The alignment part birefringence and total birefringence were measured to calculate the distortion part in this experiment. By varying the parameter of film thickness (16nm to 40nm) and molecular weight (18k to 442k), it was observed that the degree of segmental alignment had a remarkable drop in intensity for thinner and lower molecular weight samples in saturation intensity of birefringence. The result implied that the polymer-air i...[
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In this thesis, the technique of FTIR and RDS were used to study the optical anisotropy of the rubbed PS thin films on SiO
2 substrate. The birefringence of PS with saturated rubbing was investigated. Generally, the birefringence of PS was come from two sources: segmental alignment and distortion. However, the distortion part could not be measured directly. The alignment part birefringence and total birefringence were measured to calculate the distortion part in this experiment. By varying the parameter of film thickness (16nm to 40nm) and molecular weight (18k to 442k), it was observed that the degree of segmental alignment had a remarkable drop in intensity for thinner and lower molecular weight samples in saturation intensity of birefringence. The result implied that the polymer-air interface had a notable effect to the segmental alignment. The surface also had relatively lower energy in order to achieve the enhancement of the drop of segmental alignment. Also, the quantitative study of birefringence of distortion was studied by matching the information obtained by FTIR and RDS. The major information provided was the birefringence of alignment was a fraction of birefringence of distortion for the film thickness in the order of 10nm at the room temperature. It suggested the motion of segment was frozen in room temperature. The birefringence of distortion was dominant to the contribution to total birefringence. Furthermore, the relaxation of distortion was enhanced at polymer-air interface at temperature much lower than glassy temperature was observed in qualitative way.
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