Influence of Oblique Angle Deposition on Porous Polymer Film Formation

Harnessing chirality in plasmonics: from synthesis to cutting-edge applications

Nanomaterials composed of noble metals such as gold and silver, commonly known as plasmonic materials, exhibit localized surface plasmon resonance (LSPR). LSPR significantly enhances the electric field strength, thereby influencing the optical properties, for instance in surface enhanced Raman spectroscopy (SERS). Recently, chiral nanostructures, nanostructures with broken symmetry, have demonstrated significant potential in various applications, including enantiomer detection and separation, chiral catalysis, and the development of metamaterials. Due to LSPR, these nanostructures can amplify signals such as circular dichroism (CD) and optical rotatory dispersion (ORD), making them valuable in chiroptical applications. This review provides an analysis of the synthesis, properties, and applications of chiral plasmonic nanostructures. The primary synthesis methods discussed include chemical approaches, glancing angle deposition, and focused ion beam deposition, each providing precise control over the chiral properties of the nanostructures. Furthermore, the review explores the applications of these nanostructures, particularly in the detection of biomolecules (chiral sensing), asymmetric catalysis, and the development of advanced optical devices. Lastly, the review explores future directions for the field and highlights potential areas for improvement.

Designing Organic and Hybrid Surfaces and Devices with Initiated Chemical Vapor Deposition (iCVD)

The initiated chemical vapor deposition (iCVD) technique is an all-dry method for designing organic and hybrid polymers. Unlike methods utilizing liquids or line-of-sight arrival, iCVD provides conformal surface modification over intricate geometries. Uniform, high-purity, and pinhole-free iCVD films can be grown with thicknesses ranging from >15 µm to <5 nm. The mild conditions permit damage-free growth directly onto flexible substrates, 2D materials, and liquids. Novel iCVD polymer morphologies include nanostructured surfaces, nanoporosity, and shaped particles. The well-established fundamentals of iCVD facilitate the systematic design and optimization of polymers and copolymers. The functional groups provide fine-tuning of surface energy, surface charge, and responsive behavior. Further reactions of the functional groups in the polymers can yield either surface modification, compositional gradients through the layer thickness, or complete chemical conversion of the bulk film. The iCVD polymers are integrated into multilayer device structures as desired for applications in sensing, electronics, optics, electrochemical energy storage, and biotechnology. For these devices, hybrids offer higher values of refractive index and dielectric constant. Multivinyl monomers typically produce ultrasmooth and pinhole-free and mechanically deformable layers and robust interfaces which are especially promising for electronic skins and wearable optoelectronics.