| Summary: | 碩士 === 國立交通大學 === 應用化學系碩博士班 === 102 === Compared to spherical polymer particles, non-spherical polymer particles recently have drawn great attention due to their wide applications. Various fabrication techniques such as phase-separation, solvent-evaporation, and composite particles removal method have been developed to prepare non-spherical polymer particles. These methods, however, are all related to polymers in a solution state. The presence of solvent adds more complexity in controlling the particle shape. There are less techniques developed without the use of solvents. Here, we develop a new method to fabricate non-spherical polymer particles, in which solvents are not used. Spherical polymer particles are placed on top of a polymer film. After thermal annealing, the spherical polymer particles transform into non-spherical particles and finally embedded in the polymer film.
In this work, commercial polystyrene (PS) microspheres with an average diameter of 10 μm are used. Then the PS microspheres are spin-coated on poly(methyl methacrylate) (PMMA) films. Subsequently, the samples are annealed at 240 °C, which is higher than the glass transition temperatures of both polymers. The PS microspheres gradually sink into the PMMA film and transform into non-spherical PS particles. We also change the thickness of the PMMA film to study the thickness effect. For thicker PMMA films, the PS microspheres transform into hemispherical PS particles. For thinner films, the PS microspheres transform into disc-like PS particles.
In conclusion, we develop a novel method to fabricate non-spherical polymer particles. This method is easy and requires no solvent. In the future, we will explore the applications of these polymer particles.
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