Monodisperse silicon dioxide particles have been prepared by the seed growth method,and different coupling agents were used for modifying these silica particles.The results show that the size deviation of silica parti...Monodisperse silicon dioxide particles have been prepared by the seed growth method,and different coupling agents were used for modifying these silica particles.The results show that the size deviation of silica particles modified with[3 (methacryloyloxy)propyl] trimethoxysilane(KH 570) is much lower than that of silica particles modified with vinyl triethyloxy silane as the coupling agent.In the presence of ethanol and water,styrene may react with silica modified by KH 570 in dispersion polymerization.It was discovered through transmission electron microscopy and energy spectrum that the modified silica particles were successfully encapsulated with polystyrene.The number of silica particles encapsulated with polystyrene was continually decreased with the increase of the size of silica particles.Moreover,the number of silica particles was nearly unity in each SiO 2/PS composite particle when the silica particle size was greater than 410?nm.展开更多
PS/SiO2 particles with core-shell structure were synthesized by coating silica on surface of polystyrene(PS) colloidal particles.The reaction parameters,such as initial tetraethyl orthosilicate(TEOS) concentration,wat...PS/SiO2 particles with core-shell structure were synthesized by coating silica on surface of polystyrene(PS) colloidal particles.The reaction parameters,such as initial tetraethyl orthosilicate(TEOS) concentration,water concentration and reaction temperature,have been investigated to control the thickness of silica shells.The shell thickness was prepositional to the square root of the initial concentration of TEOS and first increased with increasing water concentration,reached a maximum at about 2.0 mol/L and then started decreasing beyond that concentration.It was also found that the shell thickness decreased firstly with the reaction temperature added,then tended to a constant.The so-synthesized PS/SiO2 core-shell particles were directly crystallized into 3-D ordered thin film,then sintered at 570℃ into the ordered macroporous thin film.Compared with the conditional method,the present approach avoids repeatedly filling the precursor in the templetes and save time more.展开更多
A simple and novel method is firstly reported for controlling coffee ring structure on polystyrene（PS）film surface by O2 plasma. O2 plasma treatment leads to the wettability change of PS surface from hydrophobic to ...A simple and novel method is firstly reported for controlling coffee ring structure on polystyrene（PS）film surface by O2 plasma. O2 plasma treatment leads to the wettability change of PS surface from hydrophobic to hydrophilic. For hydrophilic PS surface the coffee ring structure is avoided relying on the motion of contact line（CL） while SiO2 microspheres are left. The motion of the CL is produced based on the viscosity and Marangoni effect with the addition of polymer additives. For hydrophobic PS surface coffee ring structure still persists even with polymer additives because SiO2 microspheres transfer with the motion of the CL at the beginning of droplet evaporation and accumulate at the droplet edge at late stage with the pinning of the CL. As a result, uniform and macroscale SiO2 microspheres deposition without coffee ring structure and SiO2 microspheres deposition with coffee ring structure are controlled by O2 plasma. This method provides a new way to tune coffee ring structure with smart surface and may be potentially useful for a range of application at material deposition and diagnosing diseases.展开更多
文摘Monodisperse silicon dioxide particles have been prepared by the seed growth method,and different coupling agents were used for modifying these silica particles.The results show that the size deviation of silica particles modified with[3 (methacryloyloxy)propyl] trimethoxysilane(KH 570) is much lower than that of silica particles modified with vinyl triethyloxy silane as the coupling agent.In the presence of ethanol and water,styrene may react with silica modified by KH 570 in dispersion polymerization.It was discovered through transmission electron microscopy and energy spectrum that the modified silica particles were successfully encapsulated with polystyrene.The number of silica particles encapsulated with polystyrene was continually decreased with the increase of the size of silica particles.Moreover,the number of silica particles was nearly unity in each SiO 2/PS composite particle when the silica particle size was greater than 410?nm.
基金Supported by the National Natural Science Foundation of China(No.:20221603)
文摘PS/SiO2 particles with core-shell structure were synthesized by coating silica on surface of polystyrene(PS) colloidal particles.The reaction parameters,such as initial tetraethyl orthosilicate(TEOS) concentration,water concentration and reaction temperature,have been investigated to control the thickness of silica shells.The shell thickness was prepositional to the square root of the initial concentration of TEOS and first increased with increasing water concentration,reached a maximum at about 2.0 mol/L and then started decreasing beyond that concentration.It was also found that the shell thickness decreased firstly with the reaction temperature added,then tended to a constant.The so-synthesized PS/SiO2 core-shell particles were directly crystallized into 3-D ordered thin film,then sintered at 570℃ into the ordered macroporous thin film.Compared with the conditional method,the present approach avoids repeatedly filling the precursor in the templetes and save time more.
基金supported by the National Nature Science Foundation (Nos. 91123031, 20921003, 51403076, 21103112)he National Basic Research Program of China (No. 2012CB933802)
文摘A simple and novel method is firstly reported for controlling coffee ring structure on polystyrene（PS）film surface by O2 plasma. O2 plasma treatment leads to the wettability change of PS surface from hydrophobic to hydrophilic. For hydrophilic PS surface the coffee ring structure is avoided relying on the motion of contact line（CL） while SiO2 microspheres are left. The motion of the CL is produced based on the viscosity and Marangoni effect with the addition of polymer additives. For hydrophobic PS surface coffee ring structure still persists even with polymer additives because SiO2 microspheres transfer with the motion of the CL at the beginning of droplet evaporation and accumulate at the droplet edge at late stage with the pinning of the CL. As a result, uniform and macroscale SiO2 microspheres deposition without coffee ring structure and SiO2 microspheres deposition with coffee ring structure are controlled by O2 plasma. This method provides a new way to tune coffee ring structure with smart surface and may be potentially useful for a range of application at material deposition and diagnosing diseases.
