Song Jake, Rizvi Mehedi H, Lynch Brian B, Ilavsky Jan, Mankus David, Tracy Joseph B, McKinley Gareth H, Holten-Andersen Niels
Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States.
X-ray Science Division at the Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States.
ACS Nano. 2020 Dec 22;14(12):17018-17027. doi: 10.1021/acsnano.0c06389. Epub 2020 Dec 8.
Patchy particle interactions are predicted to facilitate the controlled self-assembly and arrest of particles into phase-stable and morphologically tunable "equilibrium" gels, which avoids the arrested phase separation and subsequent aging that is typically observed in traditional particle gels with isotropic interactions. Despite these promising traits of patchy particle interactions, such tunable equilibrium gels have yet to be realized in the laboratory due to experimental limitations associated with synthesizing patchy particles in high yield. Here, we introduce a supramolecular metal-coordination platform consisting of metallic nanoparticles linked by telechelic polymer chains, which validates the predictions associated with patchy particle interactions and facilitates the design of equilibrium particle hydrogels through limited valency interactions. We demonstrate that the interaction valency and self-assembly of the particles can be effectively controlled by adjusting the relative concentration of polymeric linkers to nanoparticles, which enables the gelation of patchy particle hydrogels with programmable local anisotropy, morphology, and low mechanical percolation thresholds. Moreover, by crowding the local environment around the patchy particles with competing interactions, we introduce an independent method to control the self-assembly of the nanoparticles, thereby enabling the design of highly anisotropic particle hydrogels with substantially reduced percolation thresholds. We thus establish a canonical platform that facilitates multifaceted control of the self-assembly of the patchy nanoparticles en route to the design of patchy particle gels with tunable valencies, morphologies, and percolation thresholds. These advances lay important foundations for further fundamental studies of patchy particle systems and for designing tunable gel materials that address a wide range of engineering applications.
据预测，斑块状粒子间相互作用有助于粒子的可控自组装，并使其聚集成相稳定且形态可调的“平衡”凝胶，这避免了在具有各向同性相互作用的传统粒子凝胶中通常观察到的聚沉相分离和随后的老化现象。尽管斑块状粒子间相互作用具有这些令人期待的特性，但由于与高产率合成斑块状粒子相关的实验限制，这种可调谐的平衡凝胶尚未在实验室中实现。在此，我们引入了一种超分子金属配位平台，该平台由通过遥爪聚合物链连接的金属纳米粒子组成，它验证了与斑块状粒子间相互作用相关的预测，并通过有限价相互作用促进了平衡粒子水凝胶的设计。我们证明，通过调整聚合物连接体与纳米粒子的相对浓度，可以有效控制粒子的相互作用价和自组装，这使得具有可编程局部各向异性、形态和低机械渗流阈值的斑块状粒子水凝胶能够凝胶化。此外，通过用竞争性相互作用使斑块状粒子周围的局部环境拥挤，我们引入了一种独立的方法来控制纳米粒子的自组装，从而能够设计出渗流阈值大幅降低的高度各向异性粒子水凝胶。因此，我们建立了一个规范平台，该平台有助于在设计具有可调价、形态和渗流阈值的斑块状粒子凝胶的过程中，对斑块状纳米粒子的自组装进行多方面控制。这些进展为进一步深入研究斑块状粒子系统以及设计适用于广泛工程应用的可调谐凝胶材料奠定了重要基础。
