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基于正负电荷间的静电作用制备了具有核-壳结构的聚苯乙烯-氧化硅(PS-SiO2)杂化颗粒,通过调节正硅酸乙酯的用量对样品的SiO2壳层厚度进行控制。利用原子力显微镜(AFM)在微观尺度上测定杂化颗粒的力-位移曲线,根据Hertz接触模型和Sneddon接触模型,考查了SiO2壳层厚度对样品压缩弹性模量的影响。扫描电子显微镜(SEM)和透射电镜(TEM)结果显示,杂化颗粒中PS内核尺寸为(197±9)nm,壳层由SiO2纳米颗粒组成,在本试验范围内杂化颗粒样品的壳厚为11~16nm。在Hertz接触模型条件下,PS微球的弹性模量为(2.2±0.5)GPa,其数值略低于PS块体材料。当SiO2壳厚由11nm增至16nm时,杂化颗粒的弹性模量从(4.4±0.6)GPa增至(10.2±1.1)GPa,其数值明显低于纯SiO2,且更接近于PS内核。
Based on the electrostatic interaction between positive and negative charges, polystyrene-silica (PS-SiO2) hybrid particles with core-shell structure were prepared. The SiO 2 shell thickness was controlled by adjusting the amount of TEOS. The force-displacement curves of hybrid particles were measured by atomic force microscopy (AFM) on microscopic scale. According to Hertz contact model and Sneddon contact model, the effect of SiO2 shell thickness on the compressive elastic modulus was investigated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results showed that the size of PS core in the hybrid particles was (197 ± 9) nm and the shell consisted of SiO2 nanoparticles. The shell thickness of the hybrid particles in this experimental range For 11 ~ 16nm. Under the Hertz contact model, the elastic modulus of PS microspheres is (2.2 ± 0.5) GPa, which is slightly lower than that of PS bulk material. The elastic modulus of hybrid particles increased from (4.4 ± 0.6) GPa to (10.2 ± 1.1) GPa when the SiO2 shell thickness increased from 11 nm to 16 nm, which was significantly lower than that of pure SiO2 and closer to the PS core.