Hybrid functional materials, constituting both inorganic and organic components, are considered potential platforms for applications in extremely diverse fields such as optics, micro-electronics, transportation, health, energy, energy storage, diagnosis, housing, environment and the highly relevant area is Internet of Things (IoT). Material properties of hybrid materials can be tuned by modification of the composition on the molecular scale to produce smart materials. Cross-cutting approaches, to synergistically couple molecular engineering and processing allows to tailor complex hybrid systems of various shapes with perfect control over size, composition, functionality, and morphology. The detailed description and discussion of variety of hybrid functional organicinorganic materials and their contribution in the designing of specific modern technologies is the prime focus of this review. There is an enormous demand for hybrid materials to provide technological breakthroughs with the most sought after being the enabling of the IoT. Interest in the field of IoT will witness exponential growth over the next decade as markets realize the true potential of realtime data acquisition for various entertainment, knowledge dissemination, defense, environmental, and healthcare applications. Many of the well-established materials, such as metals, 1 ceramics, 2-4 or plastics 5,6 cannot fulfill all technological desires for the various new applications. In addition to the early interest in structural hybrid materials based on carbon-silicon networks, many recent efforts have centered on the design of functional hybrid materials which harness the chemical activity of their components. This approach has been successfully used in recent years in the design of hybrid polymers 7 with special emphasis on structural hybrid materials based on mixed silicon-carbon networks prepared by sol-gel methods [8][9][10][11][12] which can also entrap additional active species. 13 In this field the stakes are high and scientists aim at producing structural materials with properties between those of inorganic glasses and organic polymers.8 But the expectations go beyond mechanical strength and thermal and chemical stability. These new materials are also sought for improved optical, 14-17 and electrical 18,19 properties, luminescence, 12,20-25 ionic conductivity, [26][27][28] and selectivity, 29-32 as well as chemical [33][34][35] or biochemical 36-38 activity. Chemical activity is of core importance in functional materials. Sensors, selective membranes, all sorts of electrochemical devices, from actuators to batteries or supercapacitors, supported catalysts or photoelectrochemical energy conversion cells are some important devices based on hybrid functional materials.Hybridization is a multifaceted strategy. In some cases, conducting organic polymers act just as a solid polymeric support for active species, whereas in other hybrid systems the activity of organic and inorganic species combines to reinforce or modify each other. But in every case ...

Nanostructured surfaces are common in nature and exhibit properties such as antireflectivity (moth eyes), self-cleaning (lotus leaf), iridescent colors (butterfly wings), and water harvesting (desert beetles). We now understand such properties and can mimic some of these natural structures in the laboratory. However, these synthetic structures are limited since they are not easily mass produced over large areas due to the limited scalability of current technologies such as UV-lithography, the high cost of infrastructure, and the difficulty in nonplanar surfaces. Here, we report a solution process based on block copolymer (BCP) self-assembly to fabricate subwavelength structures on large areas of optical and curved surfaces with feature sizes and spacings designed to efficiently scatter visible light. Si nanopillars (SiNPs) with diameters of ∼115 ± 19 nm, periodicity of 180 ± 18 nm, and aspect ratio of 2-15 show a reduction in reflectivity by a factor of 100, <0.16% between 400 and 900 nm at an angle of incidence of 30°. Significantly, the reflectivity remains below 1.75% up to incident angles of 75°. Modeling the efficiency of a SiNP PV suggests a 24.6% increase in efficiency, representing a 3.52% (absolute) or 16.7% (relative) increase in electrical energy output from the PV system compared to AR-coated device.

We studied the kinetics of nanopattern evolution in (polystyrene-b-polyethylene oxide) diblock copolymer thin films. Using scanning force microscopy, a highly unexpected cylindrical flipping of morphology from normal to parallel to the film plane was detected during solvent annealing of the film (with average thickness of 30 nm) at high vapor pressure. Using an in situ time-resolved light scattering device combined with an environmental cell enabled us to obtain kinetic information at different vapor pressures. The data indicated that there is a threshold value for the vapor pressure necessary for the structural transition. We propose a swelling and deswelling mechanism for the orientation flipping of the morphology. The cyclic transition occurs faster in thick films (177 nm) where the mass uptake and solvent volume fraction is smaller and therefore the driving force for phase separation is higher. We induced a stronger segregation by confining the chains in graphoepitaxially patterned substrates. As expected, the cyclic transition occurred at higher rate. Our work is another step forward to understanding the structure evolution and also controlling the alignment of block copolymer nanocylinders independently of thickness and external fields.

Thin films of polymer mixtures made by spin-coating can phase separate in two ways: by forming lateral domains, or by separating into distinct layers. The latter situation (self-stratification or vertical phase separation) could be advantageous in a number of practical applications, such as polymer optoelectronics. We demonstrate that, by controlling the evaporation rate during the spin-coating process, we can obtain either self-stratification or lateral phase separation in the same system, and we relate this to a previously hypothesised mechanism for phase separation during spin-coating in thin films, according to which a transient wetting layer breaks up due to a Marangoni-type instability driven by a concentration gradient of solvent within the drying film. Our results show that rapid evaporation leads to a laterally phase-separated structure, while reducing the evaporation rate suppresses the interfacial instability and leads to a self-stratified final film.

Physicochemical modification of implantable electrode systems is recognized as a viable strategy to enhance tissue/electrode integration and electrode performance in situ. In this work, a bench-top electrochemical process to formulate anodized ITO films with altered roughness, thickness and conducting profiles was explored. In addition, the influence of these anodized films on SH-5YSY cell proliferation, viability and focal adhesion reinforcement indicated that anodized ITO film cytocompatibility can be altered by varying the anodization current density. Furthermore, an ITO anodized films formed with a current density of 0.4 mA cm-2 showed important primary neural cell survival and promotion of neural network activity.

Standard models explaining the spin coating of polymer solutions generally fail to describe the early stages of film formation, when hydrodynamic forces control the solution behavior. Using in situ light scattering alongside theoretical and semi-empirical models, it is shown that inertial forces (which initially cause a vertical gradient in the radial solvent velocity within the film) play a significant role in the rate of thinning of the solution. The development of thickness as a function of time of a solute-free liquid (toluene) and a blend of polystyrene and poly(methyl methacrylate) cast from toluene were fitted to different models as a function of toluene partial pressure. In the case of the formation of the polymer blend film, a concentration-dependent (Huggins) viscosity formula was used to account for changes in viscosity during spin coating. A semi-empirical model is introduced, which permits calculation of the solvent evaporation rate and the temporal evolution of the solute volume fraction and solution viscosity.

The self-assembly of ultra-high molecular weight (UHMW) block copolymers (BCPs) remains a complex and timeconsuming endeavor owing to the high kinetic penalties associated with long polymer chain entanglement. In this work, we report a unique strategy of overcoming these kinetic barriers through precision solvent annealing of an UHMW polystyrene-blockpoly(2-vinylpyridine) BCP system (M w : ∼800 kg/mol) by fast swelling to very high levels of solvent concentration (ϕ s ). Phase separation on timescales of ∼10 min is demonstrated once a thickness-dependent threshold ϕ s value of ∼0.80−0.86 is achieved, resulting in lamellar feature spacings of over 190 nm. The threshold ϕ s value was found to be greater for films with higher dry thickness (D 0 ) values. Tunability of the domain morphology is achieved through controlled variation of both D 0 and ϕ s , with the kinetically unstable hexagonal perforated lamellar (HPL) phase observed at ϕ s values of ∼0.67 and D 0 values of 59−110 nm. This HPL phase can be controllably induced into an order−order transition to a lamellar morphology upon further increase of ϕ s to 0.80 or above. As confirmed by grazing-incidence small-angle X-ray scattering, the lateral ordering of the lamellar domains is shown to improve with increasing ϕ s up to a maximum value at which the films transition to a disordered state. Thicker films are shown to possess a higher maximum ϕ s value before transitioning to a disordered state. The swelling rate is shown to moderately influence the lateral ordering of the phase-separated structures, while the amount of hold time at a particular value of ϕ s does not notably enhance the phase separation process. These large period self-assembled lamellar domains are then employed to facilitate pattern transfer using a liquid-phase infiltration method, followed by plasma etching, generating ordered, high aspect ratio Si nanowall structures with spacings of ∼190 nm and heights of up to ∼500 nm. This work underpins the feasibility of a room-temperature, solvent-based annealing approach for the reliable and scalable fabrication of sub-wavelength nanostructures via BCP lithography.

A series of novel block copolymers, processable from single organic solvents and subsequently rendered amphiphilic by thermolysis, have been synthesized using Grignard metathesis (GRIM) and reversible addition–fragmentation chain transfer (RAFT) polymerizations and azide–alkyne click chemistry. This chemistry is simple and allows the fabrication of well-defined block copolymers with controllable block lengths. The block copolymers, designed for use as interfacial adhesive layers in organic photovoltaics to enhance contact between the photoactive and hole transport layers, comprise printable poly­(3-hexylthiophene)-block-poly­(neopentyl p-styrenesulfonate), P3HT-b-PNSS. Subsequently, they are converted to P3HT-b-poly­(p-styrenesulfonate), P3HT-b-PSS, following deposition and thermal treatment at 150 °C. Grazing incidence small- and wide-angle X-ray scattering (GISAXS/GIWAXS) revealed that thin films of the amphiphilic block copolymers comprise lamellar nanodomains of P3HT crystallites that can be pushed further apart by increasing the PSS block lengths. The approach of using a thermally modifiable block allows deposition of this copolymer from a single organic solvent and subsequent conversion to an amphiphilic layer by nonchemical means, particularly attractive to large scale roll-to-roll industrial printing processes.