[论文解读] Dynamics of colloidal particles formation in processing different precursors-elastically and plastically driven electronic states of atoms in lattice

Mubarak Ali, I‐Nan Lin|arXiv (Cornell University)|May 8, 2016

Pickering emulsions and particle stabilization参考文献 47被引用 11

一句话总结

本研究探讨了在脉冲加热条件下，银和金-硝酸银体系中胶体粒子形成的动力学过程，发现弹性与塑性电子态转变控制着粒子形貌。研究显示，光子辐照可将具有特定取向的塑性变形粒子组织成二维晶格或元素结构，为控制金属胶体中的纳米尺度结构提供了新途径。

ABSTRACT

Metallic colloids are frequently used in industry and provide understanding of science at micro-level to sub-micro-level along with their usage in various technological important applications. Present investigations deal with several structural hierarchies in a newly designed process and tap opportunities of nanoscale geometric structure under arisen dynamics while heating locally. On processing silver nitrate and binary composition of chloroauric acid and silver nitrate solutions under fixed ratio of pulse OFF to ON time, tiny particles of silver and binary composition having largely no specific geometry are formed at air-solution interface, while processing of chloroauric acid solution a large number of tiny particles are formed in rhombus-shaped geometry. Atoms bind in tiny particles under elastically driven electronic states and stabilize the lattice through varying levels of electronic excitations and de-excitations. Impinging electron streams 2 stretch the tiny particles; those tiny particles where stretching of plastically driven electronic states of atoms has no specific orientation propagating photons do not influence their electronic structures. On the other hand, those tiny particles where stretching of plastically driven electronic states of atoms is less and has specific orientation, propagating photons configure such tiny particles into two-dimensional lattice and where stretching of plastically driven electronic states of atoms is more and has specific orientation, propagating photons transform such electronic structures into elements. Dynamics of different morphological evolution and structural deformations in phase transformation of metallic colloids and their binary composition are discussed in this paper, which open abundant avenues to manipulate structure, thus, addressing fundamental and technologically important issues in condensed-matter physics.

研究动机与目标

• 理解在脉冲加热过程中，电子态动力学（弹性与塑性）在金属胶体形成及形貌演化中的作用。
• 研究脉冲开启/关闭时间比的变化如何影响银和金-硝酸银体系中粒子的尺寸、几何形态及结构层次。
• 确定光子传播对具有特定取向的电子态形变粒子的影响，进而导致二维晶格或元素结构的形成。
• 建立通过受控电子激发与去激发过程操纵金属胶体中纳米尺度几何结构的框架。

提出的方法

• 在固定脉冲关闭与开启时间比的条件下，对硝酸银和氯金酸-硝酸银二元溶液施加脉冲加热，以诱导局部加热和粒子成核。
• 在气液界面观察到胶体粒子的形成，形态学分析显示氯金酸体系中呈现菱形几何形态，而二元组成中则为不规则形状。
• 基于原子键的弹性（可逆）与塑性（不可逆）形变分析电子态动力学，利用电子束轰击拉伸粒子以评估结构稳定性。
• 施加光子辐照以研究其对不同程度塑性电子态拉伸粒子的影响，重点分析取向依赖的结构重排。
• 通过相变动力学监测结构演化，包括光子影响下的晶格形成与元素转变。
• 将电子激发与去激发水平与粒子几何形态及稳定性相关联，尤其关注光子传播效应。

实验结果

研究问题

• RQ1 弹性与塑性电子态转变如何影响脉冲加热过程中胶体粒子的形貌与结构层次？
• RQ2 塑性形变电子态的取向在决定胶体粒子对光子辐照响应中起什么作用？
• RQ3 为何在相同加工条件下，氯金酸溶液产生菱形粒子，而二元组成则生成不规则形状的粒子？
• RQ4 在何种条件下，传播的光子会诱导塑性形变胶体粒子形成二维晶格或元素结构？
• RQ5 电子激发与去激发之间的平衡如何在相变过程中稳定或 destabilize 胶体晶格？

主要发现

• 菱形胶体粒子仅在氯金酸溶液中于脉冲加热条件下形成，表明其对电子态动力学具有独特的结构响应。
• 氯金酸与硝酸银的二元组成在气液界面形成不规则形状的粒子，表明在相同加工条件下几何控制性较差。
• 在弹性驱动电子态下形成的粒子通过不同水平的电子激发与去激发实现稳定，维持晶格完整性。
• 电子束轰击可拉伸粒子，但仅那些具有塑性驱动电子态且无特定取向的粒子不受光子传播影响。
• 具有特定取向的塑性驱动电子态粒子在暴露于光子后重新组织为二维晶格，表明存在取向依赖的结构响应。
• 当塑性驱动电子态的拉伸程度高且具有取向特异性时，光子可将电子结构转化为元素形态，表明存在实现纳米同素异形转化的路径。