We have investigated the influence of the adsorption process on the dewetting behavior of the linear polystyrene film （LPS）, the 3-arm star polystyrene film （3SPS） and the ring polystyrene film （RPS） on the sila...We have investigated the influence of the adsorption process on the dewetting behavior of the linear polystyrene film （LPS）, the 3-arm star polystyrene film （3SPS） and the ring polystyrene film （RPS） on the silanized Si substrate. Results show that the adsorption process greatly influences the dewetting behavior of the thin polymer films. On the silanized Si substrate, the 3SPS chains exhibit stronger adsorption compared with the LPS chains and RPS chains; as a result, the wetting layer forms more easily. For LPS films, with the decrease of annealing temperature, the kinetics of polymer film changes from exponential behavior to slip dewetting. As a comparison, the stability of 3SPS and RPS films switches from slip dewetting to unusual dewetting kinetic behavior. The adsorbed nanodroplets on the solid substrate play an important role in the dewetting kinetics by reducing the driving force of dewetting and increase the resistant force of dewetting. Additionally, Brownian dynamics （BD） simulation shows that the absolute values of adsorption energy （ε） gradually increase from linear polymer （-0.3896） to ring polymer （-0.4033） and to star polymer （-0.4264）, which is consistent with the results of our adsorption experiments.展开更多
The technique of dynamic light scattering has been used to investigate the translation diffusion behavior of 8-arm star polystyrene (SPS)in a good solvent, tetrahydrofuran (THF) or benzene (BZ) and a theta solvent, cy...The technique of dynamic light scattering has been used to investigate the translation diffusion behavior of 8-arm star polystyrene (SPS)in a good solvent, tetrahydrofuran (THF) or benzene (BZ) and a theta solvent, cyclohexane (CH), by homodyne photon correlation spectroscopy .The intensityintensity autocorrelation function was analyzed by the method of cumulant. The translation diffusion coefficients have been obtained as a function of temperature and concentration. Under theta condition ,the non-concentration dependence of diffusion coefficient showed the unperturbed Gaussian state o the SPS molecular chain. The different hydrodynamic radii estimated from Stokes- Einstein equation reflected the stretch extent of the arm chain for regular star polymer. The data of diffusion activation energy of SPS in THF, BZ and CH were also obtained respectively.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.51473168,21234007,21674114,51503048,51573131 and 21374077)the grant of Guizhou Education University (No.107003001455)the Natural Science Foundation of Guizhou Province (No.QKHJC[2017]1137)
文摘We have investigated the influence of the adsorption process on the dewetting behavior of the linear polystyrene film （LPS）, the 3-arm star polystyrene film （3SPS） and the ring polystyrene film （RPS） on the silanized Si substrate. Results show that the adsorption process greatly influences the dewetting behavior of the thin polymer films. On the silanized Si substrate, the 3SPS chains exhibit stronger adsorption compared with the LPS chains and RPS chains; as a result, the wetting layer forms more easily. For LPS films, with the decrease of annealing temperature, the kinetics of polymer film changes from exponential behavior to slip dewetting. As a comparison, the stability of 3SPS and RPS films switches from slip dewetting to unusual dewetting kinetic behavior. The adsorbed nanodroplets on the solid substrate play an important role in the dewetting kinetics by reducing the driving force of dewetting and increase the resistant force of dewetting. Additionally, Brownian dynamics （BD） simulation shows that the absolute values of adsorption energy （ε） gradually increase from linear polymer （-0.3896） to ring polymer （-0.4033） and to star polymer （-0.4264）, which is consistent with the results of our adsorption experiments.
文摘The technique of dynamic light scattering has been used to investigate the translation diffusion behavior of 8-arm star polystyrene (SPS)in a good solvent, tetrahydrofuran (THF) or benzene (BZ) and a theta solvent, cyclohexane (CH), by homodyne photon correlation spectroscopy .The intensityintensity autocorrelation function was analyzed by the method of cumulant. The translation diffusion coefficients have been obtained as a function of temperature and concentration. Under theta condition ,the non-concentration dependence of diffusion coefficient showed the unperturbed Gaussian state o the SPS molecular chain. The different hydrodynamic radii estimated from Stokes- Einstein equation reflected the stretch extent of the arm chain for regular star polymer. The data of diffusion activation energy of SPS in THF, BZ and CH were also obtained respectively.
