Physical Techniques in Polymer Structure Characterization

Polymer Nanostructures Studied by Small Angle X-Ray Scattering [ 下載 PDF ]

Hsin-Lung Chen, U-Ser Jeng

This article provides an introduction on the basic principles of small angle X-ray scattering (SAXS) and its application in the studies of the structures of polymers. We first discuss how the scattering intensity profiles are related to different types of structures. Several examples are then presented to demonstrate the use of SAXS in polymer structure characterization. These examples include selfassembled block copolymers, DNA-cationic lipid complexes and semicrystalline polymers.

The Application of Transmission Electron Microscopy on the Study of Polymer Crystal Structure and Growth Mechanism [ 下載 PDF ]

Jrjeng Ruan

Fruitful ways of molecular packing in the ordered phases formed by long-chain molecules are directly linked to various applications that can be possibly developed from soft materials. However, due to the complicated natures of long-chain molecules, it is frequently met that many mechanisms able to influence and govern molecular assembly and crystallization behavior still wait to be further investigated and learned. The studies on the packing of polymer provide the possibility to reveal the knowledge at molecular level, which might be elusive for other techniques, about how these longchain molecules continuously join into the crystalline phase or other types of ordered phases. Reported in this article, single crystal diffraction pattern of Form II crystalline modification of poly- 4-methyl-pentene-1 (P4MP) obtained by TEM surprisingly helps to decipher an unusual monoclinic structure, which has lower symmetry than what have been previously learned based on X-ray powder and NMR spectrums. It is suggested that this lower symmetry of Form II results from conformational restrictions set by chain folding on the stem chirality and clinicity of helical polyolefins, and this structural analysis is well consistent with the single crystal growth habit (preferred ac growth planes). And the adjacent-reentry mechanism should be adopted in the crystal growth.

Measurements of Molecular Forces in Ultrathin Polymeric Films [ 下載 PDF ]

Arnold Chang-Mou Yang, Yu-Lun Chang, Guan-Bo Tung

By studying the local topography of incipient dewetting holes with an atomic force microscope (AFM), the recoiling force could be calculated from the local stress release resulted from hole opening. The total force acting on the thin film was determined from the mechanical interactions between the ultrathin film and a soft substrate. The capillary force was then obtained by subtracting the measured recoiling force from the total force. Detailed study on the interactions with soft substrate revealed important relations between thin film stability and the residual strain in the substrate. The behavior of molecular recoiling force and the capillary force in polymer thin films can be understood from results obtained using this approach, which shed important new light on the relatively unexplored experimental chain dynamics on the mesoscopic scales.

Application of Small Angle Light Scattering to Polymers and Complex Fluids [ 下載 PDF ]

Che-Min Chou, Po-Da Hong

Small-angle light scattering (SALS) is a useful technique to study the structural formation of jammed soft matters which are far from equilibrium. In this article, we review theory, instrument design, and applications of time-resolved dynamics and diffusing wave spectroscopy, which is believed to be one of the most important recent developed small-angle light scattering techniques.

Transmission Electron Microscopic Analysis of Nanostructures in Polymeric/Soft Materials [ 下載 PDF ]

Wen-Hsien Tseng, Rong-Ming Ho, An-Chung Su

Basic principles of imaging and diffraction in transmission electron microscopy (TEM) are briefly reviewed. This is followed by more detailed methods of specimen preparation and instrumental operation for this particular category of materials, using published examples for demonstration purposes. Strong emphasis is given to fragile and low-contrast characteristics of polymeric/soft materials; typical strategies to overcome/by-pass the inherent difficulties in dealing with this category of materials are delineated. On the basis of our previous experiences, proper instrumental specifications for TEM instruments aimed at the exclusive use of morphological/structural characterization of polymers and soft materials are suggested.

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The Application of Grism on A Multi-Wavelength Optical System [ 下載 PDF ]

Jyh-Rou Sze, Mao-Hong Lu

The wavelength division effect of grism in a multi-wavelengths optical system is discussed, the grism consist of a tranditional optical prism and a diffraction optical phase grating. A beam with designed wavelength passes through the grism will propagate along the optical axis, this property would be helpful for alignment and packagement of each component in an optical system. Finally, the influence of fabrication errors on its optical quality are discussed.

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Biochips—An Introduction to Microarray Chip and Microchip Electrophoresis [ 下載 PDF ]

Chun-Che Lin, Chien-Der Lin

Biochips refer to multifunctional microdevices fabricated on quartz, glasses, or polymer-based substrates by MEMS. Compared to conventional bioanalytical devices, biochips are more accurate, effective, and less consumptive. Due to the ability of obtaining massive bioinformation in a very short time and accelerating the drug screening, medical inspection, and biotesting, biochips are thought to be the next-generation star industry that will change the style of human life.

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Development and Application of Near Infrared Spectrometer [ 下載 PDF ]

Chih-Wen Chen, Chun-Fu Lin, Tai-Lun Huang

Near infrared (NIR) spectrometer with wavelength range from 900 nm to 1700 nm has been carried out by adopting diode array system, flat-field concave grating and InGaAs linear sensor. This type of NIR spectrometer has many advantages such as simple structure, no moving parts and rapid scanning. The article also introduces the system structure, optical path of grating, circuit architecture, stepless intergrating time, tests and applications about NIR spectrometer. We look forward to providing information for researchers and workers in related industries for reference.

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A Study of Bio-Microfluidic Manipulation Using Optimal Fuzzy Sliding-Mode Control [ 下載 PDF ]

Yung-Chiang Chung, Bor-Jiunn Wen, Chuan-You Ye, Chuang-Di Chueh

In biometric and biomedical applications, a special transporting mechanism must be designed for the µTAS (micro total analysis system) to move samples and reagents through the microchannels that connect the unit procedure components in the system. In view of this, an optimal fuzzy sliding-mode control (OFSMC) based on the 8051 microprocessor was designed and a complete microfluidic manipulated biochip system was implemented in this study, with a pneumatic pumping actuator, two feedback-signal photodiodes and flowmeters for better microfluidic management. This new technique successfully improved the efficiency of molecular biology reaction by increasing the velocity of the target nucleic acid molecules, which increased the effective collision into the probe molecules as the target molecules flow back and forth.