Herein, we demonstrate a facile approach to fully transform spherical polymeric microparticles to elongated spherocylinders containing an internal cavity under ambient and mild stirring conditions. Critical to the process is to deform the amorphous and non-crosslinked particles under glassy conditions for an unusually long time; 120 hours for the poly(styrene-co-glycidyl methacrylate) microparticles discussed in greatest detail. Larger particles in the 5 micron and greater range were markedly more susceptible to the shear imposed by stirring the aqueous dispersion. The resulting morphology is robust and kinetically frozen yet reverts to the original spherical shape if annealed above the glass transition temperature with suitable temperature or plasticizer. The volume fraction of the internal void can be modulated by particle composition and process conditions and is irregular in shape we believe as a result of a cavitation event during plastic deformation.

中文翻译：

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一种令人惊讶的温和方法，用于从流动的普通聚合物分散体中提取含有球形微粒的空腔

在此，我们展示了一种在环境和温和搅拌条件下将球形聚合物微粒完全转化为包含内腔的细长圆柱体的简便方法。该过程的关键是在玻璃状态下异常长时间地使无定形和非交联颗粒变形；120小时的聚（苯乙烯共-甲基丙烯酸缩水甘油酯）微粒进行了最详细的讨论。5微米和更大范围内的较大颗粒明显更容易受到搅拌水分散体所施加的剪切力的影响。如果在玻璃化转变温度以上用合适的温度或增塑剂退火，所得的形态是坚固的和动力学冻结的，但又会恢复到原来的球形。内部空隙的体积分数可以通过颗粒组成和工艺条件进行调节，并且形状不规则，我们认为这是塑性变形过程中的空化事件的结果。