Study On The Methods To Fabricate Stable Assembly Of Polymer Microspheres On Various Substrates

With the development of science and technology, the materials in nanometerare attracting more and more research interests. The materials in nanometer include:nanoparticles, nanotubes, nanorods, and nanowires. Because of the small size,nanoparticles possess many unique properties, such as: quantum-size effects, smallsize effects, surface effects, etc. They can be found a lot of applications in a widerange of areas: optical, electrical and magnetic devices. In many cases, theemployment of a monodispersed sample is central to the self-assembly of theseparticles into homogeneous, crystalline arrays with large domain sizes. The abilityto assemble these colloidal particles into crystalline arrays allows one to obtaininteresting and useful functionalities not only from the constituent materials butalso from the long-range, mesoscopic order that characterizes periodic structures.As a result, the formation and utilization of highly ordered structures of colloidalparticles has been an intriguing subject of research over the past several decades.The Layer-by-layer(LBL) self-assembly method develop by G. Decher is one of the －89－白立涛 吉林大学硕士学位论文 2004most perspective new methods of thin film deposition, and it has been successfullyapplied to thin films of nanoparticles and various other functional microspheres.It's simplicity and universality combined with the high quality of coatings anduniform distribution of nanoparticles opens broad perspectives for this techniqueboth in research and industry. Based on LBL method and other new methods incolloid and surface science, such as, microcontact print, lithography, we canassembly functional nano-microspheres on the surface, which can be foundapplications in many research areas. The methods and applications of microsphereshave been reviewed in chapter one. In this thesis, we have designed and synthesized a kind of polystyrenemicrospheres, which contain many sulfonic groups in their surface. At first, wesynthesized polystyrene microspheres, then we used sulfuric acid to deal with themand the polystyrene microspheres will become sulfonic polystyrene microspheres,which contain many sulfonic groups. TEM and IR were used to character them.Using three-dimensional and LBL technique, these microspheres were assembly onthe surface of substrate, which was deal with weak polyelectrolyte. By adjustingpH of system, the charge density can be controlled, and then we can assembly thesemicrospheres on a surface which is favoured for good ordering. Firstly, 3-Dmicrospheres were fabricated by dipping and vertical deposit methods, then, pH ofthe system was adjusted to let the microspheres be attracted on the surface. At thesame time, the upper layer microspheres were disposed. And we get a 2-Dmicrospheres assembly. AFM and SEM were used to character them. The result isgood. LBL's stabilization and 3-D's convenience were used in this method. By thismethod, microspheres assembly can be prepared in large scale. It gives us a newmethod to fabricate 2-D stable ordered microspheres assembly. －90－白立涛 吉林大学硕士学位论文 2004 In chapter three, microcontact method was used to print polyelectrolyte on theother kind of polyelectrolyte, the holes between the stamp and the substrate wereused to fill with microspheres by capillary. We fabricate curved surface in micronscale, and assembly our microspheres on this surface. Microscope, SEM and AFMwere used to character our result. We get an ideal result. This method can be usedto assembly microspheres on patterned surface or curved surface. In chapter four, we get a polymer using GMA, HEMA and NVP. It wasspread on a silicon wafer, then we assembly our microspheres on it. And a PDMSstamp were used to get let it becom...