The solution property of amphiphilic graft copolymer has been examined by means of NMR,TEM and viscometry. It is found that water and toluene are selective solvent for PSt- g- PEO. When it is dissolved in water, micel...The solution property of amphiphilic graft copolymer has been examined by means of NMR,TEM and viscometry. It is found that water and toluene are selective solvent for PSt- g- PEO. When it is dissolved in water, micelle can be formed with hydrophobic PSt backbone as the core and hydrophilic PEO side chains as the shell. On the other hand, in selective solvent toluene, the reversed- micelle can be formed with PEO as core and PSt as the shell. In toluene, with an increase in concentration, the conformation of PSt- g- PEO can be transformed from stretched single molecule to spherical reversed- micelle. The critical micelle concentration(CMC) is determined at different temperature and with the increase of temperature and the content of PEO the reversed- micelle can be formed in lower concentrations.展开更多
The fractal dimensions (df) of aggregates of latex paticles coated by poly(ethylene oxide)(PEO) have been measuxed in worse than θ-solvents for different concentrations MgSO4 and temperatures by means of dynamic ligh...The fractal dimensions (df) of aggregates of latex paticles coated by poly(ethylene oxide)(PEO) have been measuxed in worse than θ-solvents for different concentrations MgSO4 and temperatures by means of dynamic light scattering. For the lowest molar mass PEO studied (20kg·mol-1) the measurement df of about 2.1 was almost independent of temperature over the range studied. The value corresponds to partially reyersible cluster aggregation, which leads to relatively compact aggregates. For the highest molar mass PEO studied (600kg·mol-1), the df decreased significantly (from 2.4 to 1.7) with temperature, singnifying the generation of more ramified aggregates. The results obtained for this hydrophilic polymer contrast makedly with the aggregation of latexes stabilized by the hydrophobic polymer poly(N-isopropylacryldride)(PNIPAM) which undergoes a coil-to-globule transition.展开更多
文摘The solution property of amphiphilic graft copolymer has been examined by means of NMR,TEM and viscometry. It is found that water and toluene are selective solvent for PSt- g- PEO. When it is dissolved in water, micelle can be formed with hydrophobic PSt backbone as the core and hydrophilic PEO side chains as the shell. On the other hand, in selective solvent toluene, the reversed- micelle can be formed with PEO as core and PSt as the shell. In toluene, with an increase in concentration, the conformation of PSt- g- PEO can be transformed from stretched single molecule to spherical reversed- micelle. The critical micelle concentration(CMC) is determined at different temperature and with the increase of temperature and the content of PEO the reversed- micelle can be formed in lower concentrations.
文摘The fractal dimensions (df) of aggregates of latex paticles coated by poly(ethylene oxide)(PEO) have been measuxed in worse than θ-solvents for different concentrations MgSO4 and temperatures by means of dynamic light scattering. For the lowest molar mass PEO studied (20kg·mol-1) the measurement df of about 2.1 was almost independent of temperature over the range studied. The value corresponds to partially reyersible cluster aggregation, which leads to relatively compact aggregates. For the highest molar mass PEO studied (600kg·mol-1), the df decreased significantly (from 2.4 to 1.7) with temperature, singnifying the generation of more ramified aggregates. The results obtained for this hydrophilic polymer contrast makedly with the aggregation of latexes stabilized by the hydrophobic polymer poly(N-isopropylacryldride)(PNIPAM) which undergoes a coil-to-globule transition.
