Adventurous Research in Chemistry / Synthesis and Characterisation of Novel Nanomaterials

其目的是探索一条生产各种独特纳米颗粒的全新路线。这一前提源于化学系已经在进行的实验，在这些实验中，通过将分子包裹在超流液氦纳米液滴(LHND)中来探索分子之间的弱相互作用。这些液滴的特点是平衡温度极低(0.38K)，但它们的超稠度意味着，在气相中遇到液滴的物种将粘在液滴表面，然后向液滴中心移动，并将凝结，所有这些都在快速(&lt；1ms)的时间尺度内完成。尽管目前这项技术是化学物理学家的工具，但它在化学和材料科学中具有应用的潜力。在气相中顺序或同时添加掺杂剂将允许合成由几乎无限选择的核心和层组成的独特的纳米级物体。此外，周围的液氦是将这些纳米粒子完好无损地软着陆在基片上的理想选择，因为弱结合的氦原子将通过碰撞中的蒸发损失消耗几乎所有的碰撞能量。我们将使用各种类型的氦纳米液滴来探索多层纳米粒子的生长，从相对较小的(数万个氦原子)到极大的(&gt；&gt；108原子)。长期目标是证明，通过针孔喷嘴将液氦膨胀到真空室中，可以生长出稳定的单分散氦液滴。这种独特的来源应该提供一种新型的超低温反应堆，用于生长大的，在某种程度上，选择大小的纳米粒子，并将这些物种沉积在固体目标上。将使用高分辨率显微镜来表征形成的物种。奇特的、全新的纳米粒子，如固体外壳中包裹着液体核心(气体或液体)的纳米粒子，可能会通过这种方法生产出来，这种生长过程的可行性将成为计划中项目的一部分。

The aim is to explore an entirely novel route for producing unique varieties of nanoparticles. The premise stems from experiments already underway in the Chemistry Department in which weak interactions between molecules are being explored by encasing them in superfluid liquid helium nanodroplets (LHNDs). These droplets are characterised by an ultra-low equilibrium temperature (0.38 K) but their superfludity means that species encountering the droplets in the gas phase will stick to the droplet surface, will then move towards the centre of the droplet, and will coagulate, all within a rapid (<1 ms) timescale. Although currently the tool of chemical physicists, this technology has the potential for applications in chemistry and materials science. The sequential or simultaneous addition of dopants in the gas phase will allow the synthesis of unique nanoscale objects composed of cores and layers of almost infinite choice. Furthermore, the surrounding liquid helium is ideal for soft-landing these nanoparticles intact on substrates, since the weakly bound helium atoms will dissipate virtually all of the collision energy by evaporative loss on impact.The growth of multi-layer nanoparticles will be explored using various types of helium nanodroplets, ranging from relatively small ones (tens of thousands of helium atoms) through to extremely large ones (>>108 atoms). The long-term aim is to show that a stable source of monodisperse helium droplets can be grown by expanding liquid helium through a pinhole nozzle into a vacuum chamber. This unique source should provide a new type of ultra-low temperature reactor for growing large and, to some extent, size-selected nanoparticles and depositing these species on solid targets. High resolution microscopy will be employed to characterise the species formed. Exotic and entirely novel nanoparticles, such as ones with fluid cores (gas or liquid) encapsulated within solid shells, can potentially be produced by this route and the feasibility of this growth process will form part of the planned project.