Gummy Nanoparticles with Glassy Shells in Electrostatic Nanocomposites
Gummy Nanoparticles with Glassy Shells in Electrostatic Nanocomposites
复制标题
静电纳米复合材料中具有玻璃壳的粘性纳米颗粒
DOI：
10.1021/acs.langmuir.2c01019
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发表时间：
2022
期刊：
影响因子：
3.9
通讯作者：
Schlenoff, Joseph B.
中科院分区：
文献类型：
--
作者：
Lteif, Sandrine;Akkaoui, Khalil;Abou Shaheen, Samir;Chaaban, Maya;Weigand, Steven;Schlenoff, Joseph B.
具有不寻常和上级性能的纳米复合材料通常包含分散良好的纳米颗粒。聚二甲基硅氧烷，PDMS，提供流体状或橡胶状（交联时）的反应，这补充了无机纳米填料的高模量性质。使用PDMS作为纳米颗粒而不是连续相的系统是罕见的，因为很难制造PDMS纳米颗粒。疏水性聚合物纳米颗粒的水分散体必须经受住水和聚合物组分之间的疏水性的相当大的对比。这种挑战通常通过亲水聚合物的外壳或通过添加表面活性剂来满足。在目前的工作中，两个关键的进展，使和使用的PDMS的水胶体分散体的报告。首先，在水溶液中通过快速纳米沉淀制备具有带电氨基端基的PDMS纳米颗粒。添加负性聚电解质聚苯乙烯磺酸盐（PSS），赋予纳米颗粒玻璃状外壳，使其稳定，防止聚集。其次，当压缩成纳米复合材料时，少量的PSS导致体积模量的大幅增加。X-射线散射研究揭示了复合材料内的分层纳米结构，以4 nm PDMS胶束为最小单元。这类纳米颗粒和纳米复合材料为稳定纳米材料的液体构建块提供了新的范例。
Nanocomposites with unusual and superior properties often contain well-dispersed nanoparticles. Polydimethylsiloxane, PDMS, offers a fluidlike or rubbery (when cross-linked) response, which complements the high-modulus nature of inorganic nanofillers. Systems using PDMS as the nanoparticulate, rather than the continuous, phase are rare because it is difficult to make PDMS nanoparticles. Aqueous dispersions of hydrophobic polymer nanoparticles must survive the considerable contrast in hydrophobicity between water and the polymer component. This challenge is often met with a shell of hydrophilic polymer or by adding surfactant. In the present work, two critical advances for making and using aqueous colloidal dispersions of PDMS are reported. First, PDMS nanoparticles with charged amino end groups were prepared by flash nanoprecipitation in aqueous solutions. Adding a negative polyelectrolyte, poly(styrene sulfonate), PSS, endowed the nanoparticles with a glassy shell, stabilizing them against aggregation. Second, when compressed into a nanocomposite, the small amount of PSS leads to a large increase in bulk modulus. X-ray scattering studies revealed the hierarchical nanostructuring within the composite, with a 4 nm PDMS micelle as the smallest unit. This class of nanoparticle and nanocomposite presents a new paradigm for stabilizing liquidlike building blocks for nanomaterials.