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The formation of the surface structure of the block copolymer of styrene - isoprene ( or butadiene ) and its impact factors

Author: ZhaoYuRong
Tutor: WangXinPing
School: Zhejiang University of Technology
Course: Polymer Chemistry and Physics
Keywords: ( Or butadiene ) block copolymers , styrene - isoprene And frequency of the vibration spectrum Film-forming conditions Chain structure Surface structure
CLC: O631.3
Type: Master's thesis
Year: 2009
Downloads: 66
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Abstract

The surface properties of the polymer is determined by its surface structure. To achieve the purpose of the design and control of the polymer surface structure, it must be on the surface layer of molecules of chemical and physical properties, the state of aggregation of the surface layer structure and the formation of the surface structure of the full study. Styrene - isoprene (or butadiene) block copolymer is a thermoplastic elastomer, and have wide applications in everyday life as a pressure-sensitive adhesive and the sealing material. The same due to their respective block elements and the limitations of the technical means of the current information on their surface chemical composition rarely reported and have been reported on their surface chemical composition depth of analysis is also greater than the level of a few molecular layers. In this thesis, the sensitivity of the quasi-monolayer interface and access to rich information interface molecular structure and in situ research capabilities and frequency vibrational spectroscopy (SFG, sum Frequency Generation Vibrational Spectroscopy) technology as the main means of research, in combination with other characterization methods research into The surface formed by the influence of the film formation conditions on the formation of the surface structure of the styrene - isoprene (or butadiene) block copolymer, and the Institute structure and curing process, the relationship between the nature of the polymer solution. The following conclusions: (1) the concentration of film-forming solution significantly affect SB, SBS cast the structure and properties of the membrane surface. 1% w / v concentration, the surface of the cast film having a higher PB content, diblock SB cast film surface is substantially covered PB block is a low surface energy. As the concentration increased, the PS content of the cast film surface gradually increases. The process of casting film forming curing the disorder from the solution to the solid-state ordered self-assembly process, the final surface structure formed by the impact of the aggregation state of the polymer in solution and segments activity. Low concentrations, the polymer chain relative stretch and toluene solvent molecules in the longer the time of existence on the surface Pb may have a relatively higher migration rates and a longer migration time, and thus has a higher surface PB enrichment, even coverage entirely by PB segment. (2) the casting film formation is different from the presence of a high content of styrene / butadiene block copolymer, the surface of the spin-coated film PS and substantially independent of the film-forming solution concentration. The spin coating film formation process is a rapid evaporation of the solvent the rapid curing process, there is no low surface energy component segregation to the surface. Toluene steam treatment the PB block can be migrated to the surface, and spin-coated film and high concentration of the cast film surface in the processing after a certain time to achieve a structure covered by a layer of pure Pb. (3) the research chain structure, the film forming solvent for styrene / butadiene block copolymer surface structure formed diblock copolymer SB than triblock copolymers SBS there conducive PB component in the surface enrichment . Also found that for the two block copolymers SB only when the selective solvent cyclohexane deposition PB, the chemical structure of its surface layer was as pure PB component. Triblock copolymer SBS Whether the selective solvent is a selective solvent of the cyclohexane or PS toluene PB deposition, the chemical structure of the outermost surface layer of the three-block copolymer SBS, are made the PB with PS component coexist. (4) the use of the shaft, said the drop shape analysis (ADSA-P, Axisymmetric Drop Shape Analysis-Profile) and atomic force microscopy (AFM, Atomic Force Microscope) study the SIS membrane surface water advancing contact angle measurement process in the three-phase line at The stick-slip phenomenon and found that within a certain range of surface energy surface viscoelastic relationships, stick-slip mutation process, the water contact angle difference Δθ and the film surface FD curve approximation to a portion of the slope of a linear relationship. Description the SIS membrane surface of the stick-slip phenomenon is mainly caused due to its surface viscoelastic.

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