Templated Sub‐100‐nm‐Thick Double‐Gyroid Structure from Si‐Containing Block Copolymer Thin Films

The directed self‐assembly of diblock copolymer chains (poly(1,1‐dimethyl silacyclobutane)‐block‐polystyrene, PDMSB‐b‐PS) into a thin film double gyroid structure is described. A decrease of the kinetics of a typical double‐wave pattern formation is reported within the 3D‐nanostructure when the film thickness on mesas is lower than the gyroid unit cell. However, optimization of the solvent‐vapor annealing process results in very large grains (over 10 µm²) with specific orientation (i.e., parallel to the air substrate) and direction (i.e., along the groove direction) of the characteristic (211) plane, demonstrated by templating sub‐100‐nm‐thick PDMSB‐b‐PS films.     

Self‐Assembled Ordered Three‐Phase Au–BaTiO3–ZnO Vertically Aligned Nanocomposites Achieved by a Templating Method

Complex multiphase nanocomposite designs present enormous opportunities for developing next‐generation integrated photonic and electronic devices. Here, a unique three‐phase nanostructure combining a ferroelectric BaTiO₃, a wide‐bandgap semiconductor of ZnO, and a plasmonic metal of Au toward multifunctionalities is demonstrated. By a novel two‐step templated growth, a highly ordered Au–BaTiO₃–ZnO nanocomposite in a unique “nanoman”‐like form, i.e., self‐assembled ZnO nanopillars and Au nanopillars in a BaTiO₃ matrix, is realized, and is very different from the random three‐phase ones with randomly arranged Au nanoparticles and ZnO nanopillars in the BaTiO₃ matrix. The ordered three‐phase “nanoman”‐like structure provides unique functionalities such as obvious hyperbolic dispersion in the visible and near‐infrared regime enabled by the highly anisotropic nanostructures compared to other random structures. Such a self‐assembled and ordered three‐phase nanocomposite is obtained through a combination of vapor–liquid–solid (VLS) and two‐phase epitaxy growth mechanisms. The study opens up new possibilities in the design, growth, and application of multiphase structures and provides a new approach to engineer the ordering of complex nanocomposite systems with unprecedented control over electron–light–matter interactions at the nanoscale.     

Carbohydrate‐Based Block Copolymer Thin Films: Ultrafast Nano‐Organization with 7 nm Resolution Using Microwave Energy

Block copolymers (BCP) can self‐assemble into nanoscale patterns with a wide variety of applications in the semiconductor industry. The self‐assembly of BCPs is commonly accomplished by solvent vapor or thermal annealing, but generally these methods require long time (few hours) to obtain nanostructured thin films. In this contribution, a new and ultrafast method (using microwaves) is proposed—high temperature solvent vapor annealing (HTSVA), combining solvent vapor annealing with thermal annealing, to achieve fast and controllable self‐assembly of amphiphilic BCP thin films. A promising carbohydrate‐based BCP capable of forming cylindrical patterns with some of the smallest feature sizes is used for demonstrating how to obtain a highly ordered vertical cylindrical pattern with sub‐10 nm feature sizes in few seconds by HTSVA. HTSVA provides not only a simple way to achieve BCP fast self‐assembly in practical applications but also a tool to study the self‐assembly behavior of BCPs under extreme conditions.     

Visible‐Light‐Induced Disruption of Diselenide‐Containing Layer‐by‐Layer Films: Toward Combination of Chemotherapy and Photodynamic Therapy

A photoresponsive polyelectrolyte multilayer film containing a diselenide functional group is fabricated using an unconventional layer‐by‐layer method. The polycation backbone is constructed through copolymerization of di‐(1‐hydroxylundecyl) diselenide and 1,4‐bis(2‐hydroxyethyl)piperazine with 2,4‐diisocyanatotoluene. A common polyanion poly(styrene sulfonate) is selected as the polyanion. The obtained film can be gradually disrupted under the irradiation of mild visible light, and this process can be monitored with UV–vis spectroscopy. The residue of the film is estimated to be 17% after 5 h of irradiation. The intensity of the visible light can be as low as 50 mW cm^?2, which is even weaker than the sunlight. The cytotoxicity of the building blocks is evaluated in MTT assays using human hepatic cell line (L‐02), and the results are satisfactory. Further tests show that cells can grow in a regular manner on this film, indicating good biocompatibility. In addition, the film can be used to achieve cargo loading and controlled release. Considering that light can not only trigger controlled release but also act as part of the therapy itself (photodynamic therapy), this system shows hope for further development into a platform for the combination of chemotherapy and photodynamic therapy, especially for applications concerning skin.     

Hydrogen‐Bonded Molecular Networks of Melamine and Cyanuric Acid on Thin Films of NaCl on Au(111)

Self‐assembly of organized molecular structures on insulators is technologically very relevant, but in general rather challenging to achieve due to the comparatively weak molecule–substrate interactions. Here the self‐assembly of a bimolecular hydrogen‐bonded network formed by melamine (M) and cyanuric acid (CA) on ultrathin NaCl films grown on a Au(111) surface is reported. Using scanning tunneling microscopy under ultrahigh‐vacuum conditions it is demonstrated that it is possible to exploit strong intermolecular forces in the M–CA system, resulting from complementary triple hydrogen bonds, to grow 2D bimolecular networks on an ultrathin NaCl film that are stable at a relatively high temperature of ≈160 K and at a coverage below saturation of the first molecular monolayer. These hydrogen‐bonded structures on NaCl are identical to the self‐assembled structures observed for the M–CA system on Au(111), which indicates that the molecular self‐assembly is not significantly affected by the isolating NaCl substrate.