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Gummy Nanoparticles with Glassy Shells in Electrostatic Nanocomposites
Langmuir ( IF 3.7 ) Pub Date : 2022-07-25 , DOI: 10.1021/acs.langmuir.2c01019
Sandrine Lteif 1 , Khalil Akkaoui 1 , Samir Abou Shaheen 1 , Maya Chaaban 1 , Steven Weigand 2 , Joseph B Schlenoff 1
Affiliation  

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.

中文翻译:

静电纳米复合材料中具有玻璃壳的胶状纳米颗粒

具有不寻常和卓越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)响应,补充了无机纳米填料的高模量特性。使用 PDMS 作为纳米颗粒而非连续相的系统很少见,因为很难制造 PDMS 纳米颗粒。疏水性聚合物纳米粒子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。这一挑战通常通过亲水聚合物外壳或添加表面活性剂来解决。在目前的工作中,报告了制备和使用 PDMS 水性胶体分散体的两个关键进展。第一的,通过在水溶液中的快速纳米沉淀制备具有带电氨基端基的 PDMS 纳米颗粒。添加负聚电解质聚(苯乙烯磺酸盐)PSS,使纳米粒子具有玻璃壳,使其稳定以防止聚集。其次,当压缩成纳米复合材料时,少量的 PSS 会导致体积模量大幅增加。X 射线散射研究揭示了复合材料内的分层纳米结构,其中 4 nm PDMS 胶束作为最小单元。这类纳米颗粒和纳米复合材料为稳定纳米材料的液体状构件提供了新的范例。少量的 PSS 会导致体积模量大幅增加。X 射线散射研究揭示了复合材料内的分层纳米结构,其中 4 nm PDMS 胶束作为最小单元。这类纳米颗粒和纳米复合材料为稳定纳米材料的液体状构件提供了新的范例。少量的 PSS 会导致体积模量大幅增加。X 射线散射研究揭示了复合材料内的分层纳米结构,其中 4 nm PDMS 胶束作为最小单元。这类纳米颗粒和纳米复合材料为稳定纳米材料的液体状构件提供了新的范例。
更新日期:2022-07-25
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