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用无皂乳液聚合法制备了粒径为200-500nm的单分散聚苯乙烯(PS)微球。依靠正负电荷间作用力将样品分散在经过亲水处理的硅热氧化片刚性衬底上,借助原子力显微镜纳米压痕技术测定了PS颗粒样品的力学性质;依据样品的力-位移曲线,根据弹性力学接触模型,计算出PS微球样品的压缩杨氏模量为2-3 GPa(Hertz模型)和2-6 GPa(Sneddon模型)。结果表明,微球样品的杨氏模量计算值略低于PS块体材料,且随着粒径的增加而缓慢增大。Hertz模型更适于计算本文制备的亚微米级PS微球的压缩杨氏模量。
Monodispersed polystyrene (PS) microspheres with a particle size of 200-500 nm were prepared by soap-free emulsion polymerization. Relying on the force between positive and negative charges, the samples were dispersed on the hydrophilic substrate treated by hydrophilic treatment. The mechanical properties of PS particles were determined by atomic force microscopy (Nanoindentation) technique. According to the force-displacement curves of samples, Elastic mechanics contact model, the compressive Young’s modulus of PS microspheres was calculated as 2-3 GPa (Hertz model) and 2-6 GPa (Sneddon model). The results show that the Young’s modulus of the microsphere sample is slightly lower than that of the PS bulk material and increases slowly with the increase of the particle size. The Hertz model is more suitable for calculating the compressive Young’s modulus of the submicron PS microspheres prepared here.