A novel polymer/SiO2 hybrid emulsion(PAES)was prepared by directly mixing colloidal silica with polyacrylate emulsion(PAE)modified by a saline coupling agent.The sol-gel-derived thin films were obtained by addition of...A novel polymer/SiO2 hybrid emulsion(PAES)was prepared by directly mixing colloidal silica with polyacrylate emulsion(PAE)modified by a saline coupling agent.The sol-gel-derived thin films were obtained by addition of co-solvents into the PAES.The effects ofγ-methacryloxypropyltrimethoxysilane(KH-570)content and co-solvent on the properties of PAES films were investigated.Dynamic laser scattering(DLS)data indicate that the average diameter of PAES(96 nm)is slightly larger than that of PAE(89 nm).Transmission electron microscopy (TEM)photo discloses that colloidal silica particles are dispersed uniformly around polyacrylate particles and some of the colloidal silica particles are adsorbed on the surface of PAE particles.The crosslinking degree data and Fourier transform infrared(FT-IR)spectra confirm that the chemical structure of the PAES is changed to form Si-O-Si-polymer crosslinking networks during the film formation.Atomic force microscope(AFM)photos show the solvent induced sol-gel process of colloidal silica and the Si-based polymer distribution on the film surface of the dried PAES.Thermogravimetric analysis(TGA)curves demonstrate that the PAES films display much better thermal stability than PAE.展开更多
The chemical mechanical polishing (CMP) process has become a widely accepted global planarization technology.The abrasive material is one of the key elements in CMP.In the presented paper,an Ag-doped colloidal SiO2 ab...The chemical mechanical polishing (CMP) process has become a widely accepted global planarization technology.The abrasive material is one of the key elements in CMP.In the presented paper,an Ag-doped colloidal SiO2 abrasive is synthesized by a seed-induced growth method.It is characterized by time-of-flight secondary ion mass spectroscopy and scanning electron microscopy to analyze the composition and morphology.The CMP performance of the Ag-doped colloidal silica abrasives on sapphire substrates is investigated.Experiment results show the material removal rate (MRR) of Ag-doped colloidal silica abrasives is obviously higher than that of pure colloidal silica abrasives under the same testing conditions.The surfaces that are polished by composite colloidal abrasives exhibit lower surface roughness (Ra) than those polished by pure colloidal silica abrasives.Furthermore,the acting mechanism of Ag-doped colloidal SiO2 composite abrasives in sapphire CMP is analyzed by X-ray photoelectron spectroscopy,and analytical results show that element Ag forms Ag2O which acts as a catalyst to promote the chemical effect in CMP and leads to the increasing of MRR.展开更多
A rigid colloidal silica template was formed by self-assembly of the monodispersed silica spheres prepared according to Stober method. The silica template is highly ordered, which was verified by bright color effect d...A rigid colloidal silica template was formed by self-assembly of the monodispersed silica spheres prepared according to Stober method. The silica template is highly ordered, which was verified by bright color effect due to Bragg diffraction and the results of SEM. The free radical polymerization of styrene was allowed within the interstices of the rigid template to result in the formation of the three-dimensional periodic silica/polystyrene nano-composites. The titled porous polystyrene was prepared by chemical decomposition of the template with concentrated aqueous hydrofluoric acid. Scanning electron microscopy characterization showed that the macroporous polystyrene has ordered arrays of the uniform pores replicated from the template. Moreover, it was found that the morphology of the as-synthesized macroporous polystyrene was greatly affected by the connectivity of the silica spheres treated under different conditions.展开更多
基金Supported by the Program for New Century Excellent Talents in University（NCET-08-0204） National Natural Science Foundation of China（20976060） the Scientific Research Foundation for the Returned Overseas Chinese Scholars State Edu-cation Ministry （China）
文摘A novel polymer/SiO2 hybrid emulsion(PAES)was prepared by directly mixing colloidal silica with polyacrylate emulsion(PAE)modified by a saline coupling agent.The sol-gel-derived thin films were obtained by addition of co-solvents into the PAES.The effects ofγ-methacryloxypropyltrimethoxysilane(KH-570)content and co-solvent on the properties of PAES films were investigated.Dynamic laser scattering(DLS)data indicate that the average diameter of PAES(96 nm)is slightly larger than that of PAE(89 nm).Transmission electron microscopy (TEM)photo discloses that colloidal silica particles are dispersed uniformly around polyacrylate particles and some of the colloidal silica particles are adsorbed on the surface of PAE particles.The crosslinking degree data and Fourier transform infrared(FT-IR)spectra confirm that the chemical structure of the PAES is changed to form Si-O-Si-polymer crosslinking networks during the film formation.Atomic force microscope(AFM)photos show the solvent induced sol-gel process of colloidal silica and the Si-based polymer distribution on the film surface of the dried PAES.Thermogravimetric analysis(TGA)curves demonstrate that the PAES films display much better thermal stability than PAE.
基金the National Natural Science Foundation of China
文摘The chemical mechanical polishing (CMP) process has become a widely accepted global planarization technology.The abrasive material is one of the key elements in CMP.In the presented paper,an Ag-doped colloidal SiO2 abrasive is synthesized by a seed-induced growth method.It is characterized by time-of-flight secondary ion mass spectroscopy and scanning electron microscopy to analyze the composition and morphology.The CMP performance of the Ag-doped colloidal silica abrasives on sapphire substrates is investigated.Experiment results show the material removal rate (MRR) of Ag-doped colloidal silica abrasives is obviously higher than that of pure colloidal silica abrasives under the same testing conditions.The surfaces that are polished by composite colloidal abrasives exhibit lower surface roughness (Ra) than those polished by pure colloidal silica abrasives.Furthermore,the acting mechanism of Ag-doped colloidal SiO2 composite abrasives in sapphire CMP is analyzed by X-ray photoelectron spectroscopy,and analytical results show that element Ag forms Ag2O which acts as a catalyst to promote the chemical effect in CMP and leads to the increasing of MRR.
基金by the National Natural Science Foundation of China (Grant No. 29774038), and the National Key Project for Fundamental Research, "Macromolecular Condensed State" of the Ministry of Science and Technology of China. The support by the Polymer Physics Labor
文摘A rigid colloidal silica template was formed by self-assembly of the monodispersed silica spheres prepared according to Stober method. The silica template is highly ordered, which was verified by bright color effect due to Bragg diffraction and the results of SEM. The free radical polymerization of styrene was allowed within the interstices of the rigid template to result in the formation of the three-dimensional periodic silica/polystyrene nano-composites. The titled porous polystyrene was prepared by chemical decomposition of the template with concentrated aqueous hydrofluoric acid. Scanning electron microscopy characterization showed that the macroporous polystyrene has ordered arrays of the uniform pores replicated from the template. Moreover, it was found that the morphology of the as-synthesized macroporous polystyrene was greatly affected by the connectivity of the silica spheres treated under different conditions.
