Triblock Copolymer Surfactant Research Articles

Adjuvant Pluronic F68 Is Compatible with a Plant Root-Colonizing Probiotic, Pseudomonas chlororaphis O6

Plant probiotic bacteria are being increasingly used to maximize both the productivity and quality of field crops. Pseudomonas chlororaphis O6 (PcO6) is a plant root colonizer with probiotic activities. This bacterium produces an array of metabolites, including a group of phenazines that are functional in plant protection. The paper reports responses of PcO6 to a nonionic triblock copolymer surfactant, Pluronic F68. This Pluronic exhibits membrane “healing” activity and improves cryopreservation recovery in eukaryotic cells. The product is FDA-approved and is applied as an adjuvant in formulations used in agriculture, medicine, and biotechnology. Growth of PcO6 on lysogeny broth at 25 °C was unhindered by 0.1 and 1.0 g/L F68, reduced at 10 g/L, and with significant inhibition at 100 g/L F68; micelle formation could account for inhibited growth at higher doses. Phenazine production was not changed by F68, whereas the surfactant activity of F68 induced the spread of bacterial colonization on 0.5% agar. Exposure of cells to fluorescein-labeled F68 resulted in intense fluorescence, stable to washing, showing a direct association of the Pluronic with the bacterium. However, neither protection nor harm was found for PcO6 cells suspended in either 0.1% or 1% F68 after three freeze (−20 °C)/thaw cycles. These findings suggest that F68 could be compatible for use in agricultural formulations with little effect on probiotics such as PcO6.

Polydimethylsiloxane Polymerized Emulsions for Acoustic Materials Prepared Using Reactive Triblock Copolymer Surfactants.

Porous polymers have interesting acoustic properties including wave dampening and acoustic impedance matching and may be used in numerous acoustic applications, e.g., waveguiding or acoustic cloaking. These materials can be prepared by the inclusion of gas-filled voids, or pores, within an elastic polymer network; therefore, porous polymers that have controlled porosity values and a wide range of possible mechanical properties are needed, as these are key factors that impact the sound-dampening properties. Here, the synthesis of acoustic materials with varying porosities and mechanical properties that could be controlled independent of the pore morphology using emulsion-templated polymerizations is described. Polydimethylsiloxane-based ABA triblock copolymer surfactants were prepared using reversible addition-fragmentation chain transfer polymerizations to control the emulsion template and act as an additional cross-linker in the polymerization. Acoustic materials prepared with reactive surfactants possessed a storage modulus of ∼300 kPa at a total porosity of 71% compared to materials prepared using analogous nonreactive surfactants that possessed storage modulus values of ∼150 kPa at similar porosities. These materials display very low longitudinal sound speeds of ∼35 m/s at ultrasonic frequencies, making them excellent candidates in the preparation of acoustic devices such as metasurfaces or lenses.

Controlling Kinetic Pathways in Demixing Microgel-Micelle Mixtures.

We investigate the temperature-dependent phase behavior of mixtures of poly(N-isopropylacrylamide) (pNIPAM) microgel colloids and a triblock copolymer (PEO-PPO-PEO) surfactant. Usually, gelation in these systems results from an increase in temperature. Here we investigate the role of the heating rate, and surprisingly, we find that this causes the mechanism of aggregation to change from one which is driven by depletion of the microgels by the micelles at low temperatures to the association of the two species at high temperatures. We thus reveal two competing mechanisms for attractions between the microgel particles which can be controlled by changing the heating rate. We use this heating-rate-dependent response of the system to access multiple structures for the same system composition. Samples were found to demix into phases rich and poor in microgel particles at temperatures below 33 °C, under conditions where the microgels particles are partially swollen. Under rapid heating full demixing is bypassed, and gel networks are formed instead. The temperature history of the sample, therefore, allows for kinetic selection between different final structures, which may be metastable.

Surfactant-assisted mesopores in hierarchical metal-organic frameworks for the immobilization of model protein Cyt c.

A hierarchical metal-organic framework, H-mMOF-1 (representing hierarchical medi-MOF-1), was successfully synthesized by the coassembly of MOF starting reagents and a triblock copolymer surfactant F127. The obtained H-mMOF-1 retained its microporous structure but also exhibited mesopores with a size range from 3 to 10 nm. The mesopores were able to accommodate protein Cyt c with a loading capacity of 160 mg g-1. The surfactant-assisted synthesis of hierarchical MOFs provides promising applications for enzyme immobilization.

Effective Controlling of Ni3S2/MoS2 Porous Hollow Spheres on Ni Foam by Non‐ionic Surfactant Micelles for Oxygen Evolution Reaction

AbstractThe hollow sphere structure has attracted various attention in the catalytic field due to its high specific surface. The good dispersion and morphology of hollow spheres are important to provide high active sites. It is a big challenge to control the morphology and distribution of the active materials during synthesis. Serious deformation and uneven distribution of the spheres were usually obtained due to inappropriate templates. A facile one‐step hydrothermal method using micelles of triblock copolymer surfactant P123 was adopted to in‐situ grow Ni3S2/MoS2 porous hollow spheres on Ni foam with uniform distribution. The as‐produced Ni3S2/MoS2 porous hollow spheres have been demonstrated to have excellent oxygen evolution reaction catalytic performance as integrated electrodes. Low overpotentials of 314 mV and 337 mV have been achieved at current densities of 50 mA cm−2 and 100 mA cm−2 with a Tafel slope of 57 mV dec−1 and an excellent long‐term stability, which is better than other Ni‐base material.

Modeling sizing emulsion droplet deposition onto silica using all-atom molecular dynamics simulations

Understanding structure–function relationships of the matrix–fiber interphase is important for the future design of composites with enhanced performance. This interphase structure is determined in part by sizing, an emulsion of epoxy film-former, silane coupling agent , and surfactant applied to fibers prior to work-up and resin impregnation . The multicomponent, microphase-separated nature of sizing makes it difficult to study using experiments and continuum-level simulations. In this study, microsecond all-atom molecular dynamics (MD) simulations are used to elucidate the dynamics of complex multicomponent sizing droplets on glass fiber surfaces. We analyze droplet/surface properties such as spreading factor, component density profiles, and spatial distribution of hydrogen bonds. From these observables, we show that the triblock copolymer surfactant enhances wetting of the epoxy resin film former on the glass surface, whereas the silane coupling agent slows down the spreading by pinning the droplet via siloxyl-surface hydrogen bonding. This work takes a step toward systematic understanding of the functionality of sizing in allowing pre-cured resin to wet glass surfaces in the context of composite lay-up. • Spreading dynamics of sizing droplets on silica depend on their composition. • Coupling agents deposit in rings that pin droplet contact lines and slow spreading.

Promising solar photodegradation of RY 86 by hydrophilic F127 (pluronic) aided nano cobalt ferrite and its biomedical applications

To our surprise, we effectively excelled in developing the hydrophilic, non-ionic and water soluble triblock copolymer surfactant F127 (pluronic) aided spinel cobalt ferrite (CFO) nanoparticles. The crystalline nature and surface morphology of F127 aided CFO nanoparticles have been confirmed laboriously by XRD, HR-TEM, DLS, FT-RAMAN, FT-IR, UV-DRS, and SEM-EDX. SEM confirms undeclared rod-like structure and HR-TEM supports a shape similar to quasi-spherical morphology. The band gap investigation report that the Eg value of F127 aided CFO is around 1.24 eV. We found the fact that, in the UV/solar light degradation of hazardous Reactive Yellow 86 (RY 86), the photocatalytic activity of F127 aided CFO nanoparticles was accelerated by the presence of H2O2. F127 is a surfactant that played a key role in the enhanced activity of F127 aided CFO nanoparticles. By using an external magnetic field, the catalyst can be recovered from the fluid medium and thereby reused. The feasible mechanism for active liquid phase photodegradation of RY 86 has also been developed. Therefore, we assure that the novel spinel F127 aided CFO nanoparticles will shed more light for the wastewater treatment system because of its effective photocatalytic and reusable behavior. In conjunction, the antibacterial function and cytotoxicity are also performed.

Oxidative degradation of triblock-copolymer surfactant and its effects on self-assembly

Oxidative degradation of triblock-copolymer surfactant and its effects on self-assembly

Roles of the Coupling Agent and Surfactant in Droplet Structure in Sizing Emulsions: A Molecular Dynamics Simulations Study

Sizing emulsions used as glass fiber surface treatments in composites manufacturing are aqueous suspensions of hydrophobic film formers, surface coupling agents, and surfactants. We employ all-atom molecular dynamics simulations to characterize droplet structures in several aqueous blends of the film-former diglycidyl ether of bisphenol A, coupling agent glycidoxypropyl trimethoxysilane, and a triblock copolymer surfactant (Pluronic L35 PEO/PPO copolymer). We show that the quasi-equilibrium states of emulsion droplets are invariant to different initial configurations. We examine the role of the surfactant in determining coupling agent partitioning between the droplet shell and corona and coupling agent cluster size distributions. This work takes a step toward systematic understanding of the sizing chemistry to optimize the interface between the glass and the resin in commercially relevant composites.

Oxidative degradation of triblock-copolymer surfactant and its effects on self-assembly

We investigate the degradation behaviour of a triblock-copolymer surfactant made from polyethylene oxide (PEO) and polypropylene oxide (PPO) (PEO-PPO-PEO), highlighting how the aggregation behaviour of this polymer in water alters with ageing. Samples aged at room temperature were compared to samples degraded using accelerated ageing at elevated temperatures. We find that large mass losses occurred to the polymer surfactant which resulted in a change in the aggregation behaviour, with larger, rod-like or planar aggregates forming at longer degradation times. We look at how this change in aggregation behaviour changes the formulation stability of these polymers, specifically, the interaction of the polymer surfactant with poly(N-isopropylacrylamide) microgels. It is known that these species associate and form gels at elevated temperatures. This paper highlights how commonly used polymeric surfactants can degrade over time, resulting in dramatic changes to aggregation behaviour and therefore, formulation properties.

Effects of Film Flow and a Surfactant on Scale Formation in Falling Film Evaporators for Seawater Desalination

Horizontal tube falling film evaporators are commonly used in multiple-effect distillation (MED) plants for seawater desalination. Scale formation on the evaporator tubes strongly depends on film flow characteristics. The thickness of the liquid film on a horizontal tube was measured in a test rig with a high-resolution optical micrometer. Furthermore, scale formation was studied with artificial seawater in a horizontal tube falling film evaporator at pilot plant scale. The effects of a polyoxyalkylene triblock copolymer surfactant on falling film flow and scale formation were investigated at different wetting rates. Film thicknesses on the bottom of the tube exceed film thicknesses on the top by an order of magnitude. The thinnest film is formed on the tube sides. The mean film thickness increases with increasing wetting rate. The scale formation on the top of the tube is stronger than that at the bottom. The highest scale thickness was measured at the tube sides. Scale mass and scale layer thickness increase with decreasing wetting rate. As the minimum and the mean film thickness increase and surface waves are mostly damped in presence of the surfactant, the mass transfer resistance is higher and, thus, scale formation is reduced.

Facile synthesis of silica‐polymer monoliths using nonionic triblock copolymer surfactant for efficient removal of radioactive pollutants from contaminated seawater

AbstractHere, we introduce a highly porous functional mesoscopically silica‐polymer composite based on silica monolith‐conjugated thiourea/formaldehyde copolymer. The developed nanostructure enables selective and fast removal of the radioactive pollutants strontium (Sr[II]) and cesium (Cs[I]) ions from contaminated seawater. The silica/polymer composite was synthesized by introducing thiourea/formaldehyde solution into tetramethoxy orthosilicate/triblock copolymer emulsion. The chemical and textural features of the synthesized silica/thiourea‐formaldehyde polymer composite (SiO2‐TUF) were characterized using Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, scanning electron microscope, high‐resolution transmission electron microscope, energy dispersive X‐ray analysis, dynamic light scattering, thermal analysis, and N2 adsorption/desorption measurements. The synthesized microporous SiO2‐TUF showed excellent cesium and strontium ions removal ability, reaching a maximum adsorption capacity of 78.2 and 40.3 mg g−1 for Sr(II) and Cs(I), respectively. When tested with seawater contaminated with radioactive cesium and strontium, SiO2‐TUF was able to selectively target Sr(II) and Cs(I) ions. Among the different types of adsorption isotherms investigated, Sips isotherm showed the best fit with R2 > 0.990. The kinetic studies showed that the pseudo‐second‐order model gave the best description of the uptake process.

En route to single-step, two-phase purification of carbon nanotubes facilitated by high-throughput spectroscopy

Chirality purification of single-walled carbon nanotubes (SWCNTs) is desirable for applications in many fields, but general utility is currently hampered by low throughput. We discovered a method to obtain single-chirality SWCNT enrichment by the aqueous two-phase extraction (ATPE) method in a single step. To achieve appropriate resolution, a biphasic system of non-ionic tri-block copolymer surfactant is varied with an ionic surfactant. A nearly-monochiral fraction of SWCNTs can then be harvested from the top phase. We also found, via high-throughput, near-infrared excitation-emission photoluminescence spectroscopy, that the parameter space of ATPE can be mapped to probe the mechanics of the separation process. Finally, we found that optimized conditions can be used for sorting of SWCNTs wrapped with ssDNA as well. Elimination of the need for surfactant exchange and simplicity of the separation process make the approach promising for high-yield generation of purified single-chirality SWCNT preparations.

Dynamic Coloration of Complex Emulsions by Localization of Gold Rings Near the Triphase Junction.

Multiphase microscale emulsions are a material platform that can be tuned and dynamically configured by a variety of chemical and physical phenomena, rendering them inexpensive and broadly programmable optical transducers. Interface engineering underpins many of these sensing schemes but typically focuses on manipulating a single interface, while engineering of the multiphase junctions of complex emulsions remains underexplored. Herein, multiphilic triblock copolymer surfactants are synthesized and assembled at the triphase junction of a dynamically reconfigurable biphasic emulsion. Tailoring the linear structure and composition of the polymer surfactants provides affinity to each phase of the complex emulsion (hydrocarbon, fluorocarbon, and continuous water phase), yielding selective localization of polymers around the triphase junction. Conjugation of these polymers with gold nanoparticles, forming structured rings, affords a dynamic reflected isotropic structural color that tracks with emulsion morphology, demonstrating the uniquely enabling nature of a functionalized triphase interface. This color is the result of interference of light along the internal hydrocarbon/fluorocarbon interface, with the gold nanoparticles scattering and redirecting light into total internal reflection competent paths. Thus, the functionalization of the triphase junction renders complex emulsions colorimetric sensors, a powerful tool toward sensitive and simple sensing platforms.

Construction of mesoporous ZnFe2O4-g-C3N4 nanocomposites for enhanced photocatalytic degradation of acridine orange dye under visible light illumination adopting soft- and hard-template-assisted routines

In this investigation, triblock copolymer surfactant (F-108) as a soft template and mesoporous silica (MCM-41) as a hard template were endorsed to establish mesoporous ZnFe2O4-g-C3N4 nanocomposites of improved features. Photocatalytic remediation of acridine orange dye was endorsed to test the efficiency of the established nanocomposites when exposed to visible light. It has been affirmed by the surface characterization investigation that established nanocomposites acquired improved specific surface areas when correlated with the surface areas of both pure ZnFe2O4 nanoparticles (NPs) and pure g-C3N4 nanosheets. In addition, TEM analysis depicted that ZnFe2O4 nanoparticles (NPs) are homogenously spread on the g-C3N4 surface. Besides, synthesized ZnFe2O4-g-C3N4 nanocomposite accommodating 3 wt.% ZnFe2O4 NPs exhibited reinforced efficacy against photocatalytic decomposition of acridine orange dye when related to that of neat mesoporous ZnFe2O4 NPs as well as that of g-C3N4 nanosheets. Evidently, the photocatalytic remediation achievement of acridine orange acquired by 3 wt.% ZnFe2O4@g-C3N4 nanocomposites was found to be 4.4 times the achievement acquired by neat mesoporous ZnFe2O4 NPs. At the same time, it was 6.3 times the achievement acquired by neat g-C3N4 nanosheets. The fast transference of the reactant molecules through the mesoporous texture, the suppressed rate of the photoinduced charges' recombination, the boosted separation between charges, the diminished band gap energy besides the extended surface area of the synthesized nanocomposites could be considered the most important considerations that contribute strongly to the superior photocatalytic achievement of the synthesized ZnFe2O4-g-C3N4 nanocomposite towards photocatalytic remediation of acridine orange dye. Furthermore, the homogenous distribution of the small-sized ZnFe2O4 NPs onto the nanosheets’ surface participated also the photocatalytic progression of the synthesized nanocomposites. The regenerated ZnFe2O4-g-C3N4 nanocomposite exhibited extensive stability and durability even after recycling up to five runs.

Development of mesoporous Bi2WO6/g-C3N4 heterojunctions via soft- and hard-template-assisted procedures for accelerated and reinforced photocatalytic reduction of mercuric cations under vis light irradiation

In this study, mesoporous Bi2WO6/g-C3N4 heterojunctions were developed using soft and hard templates [triblock copolymer surfactant (F127) and mesoporous silica (MCM-41), respectively]. The performance of the developed heterojunctions was assessed through the photocatalytic reduction of mercuric cations under Vis light illumination, with HCOOH being adopted to provide sacrificial holes agent. Surface measurements demonstrated that the fabricated specimens acquired large specific surface areas when compared with the neat ingredient. Furthermore, a transmission electron microscopy (TEM) analysis of the developed heterojunctions showed the homogeneous distribution of the spherical Bi2WO6 nanoparticles (NPs) on the surface of g-C3N4 nanosheets. Meanwhile, an accelerated rate (700 μ·mol·g−1·h−1) of photocatalytic mercuric cation reduction with improved efficiency (approximately 100%), compared with those of the pure ingredients [rate of 55 μ·mol·g−1·h−1 and efficiency of 13% for g-C3N4 nanosheets; rate of 95 μ·mol·g−1·h−1 and efficiency of 20% for mesoporous Bi2WO6 NPs], was accomplished via testing of the Bi2WO6/g-C3N4 heterojunction comprising 4 wt% Bi2WO6 after 40 min of illumination. Evidently, the efficiency of the photocatalytic reduction of mercuric cations endorsing the Bi2WO6/g-C3N4 heterojunction comprising 4 wt% Bi2WO6 NPs is 7.7 and 5 times more when compared with those of the neat g-C3N4 nanosheets and mesoporous Bi2WO6 NPs, respectively. The improved performance of the fabricated heterojunctions in the photocatalytic reduction of mercuric cations could be ascribed to i) fast diffusion of the mercuric cations through the mesoporous texture to the active ensembles, ii) greater specific surface area, iii) limited bandgap magnitude, iv) homogenous dispersion of the Bi2WO6 NPs on the surface of the nanosheets, and v) finite particle dimension of the mesoporous Bi2WO6 NPs. The durability and stability of the Bi2WO6/g-C3N4 heterojunctions were confirmed via their recyclability, which was maintained for up to five runs without pronounced activity loss.

Soft and hard templates assisted synthesis mesoporous CuO/g-C3N4 heterostructures for highly enhanced and accelerated Hg(II) photoreduction under visible light

Herein, triblock copolymer surfactant (F127) and mesoporous silica (MCM-41) as soft and hard templates were employed to synthesize of mesoporous CuO/g-C3N4 heterostructures with large surface areas for Hg(II) photoreduction in existence of formic acid as a holes sacrificial. TEM image for mesoporous CuO/g-C3N4 indicated that CuO NPs are homogeneously distributed with spherical shape in particle size ~5 nm onto the surface of g-C3N4. Mesoporous 2%CuO/g-C3N4 heterostructure was achieved a high Hg(II) photoreduction rate of 628.74 µmolg−1h−1 and high photoreduction efficiency of ~100% within 50 min compared with the pure either mesoporous CuO NPs (130.11 µmolg−1h−1, 21%) and g-C3N4 (88.54 µmolg−1h−1, 14%). The highest Hg(II) photoreduction rate achieved was 628.74 µmolg−1h−1, which is 4.83 and 7.1 magnitudes stronger than mesoporous CuO NPs and g-C3N4. The excellent photocatalytic performance of mesoporous CuO/g-C3N4 heterostructures for Hg(II) photoreduction is referred to highly dispersed mesoporous CuO NPs with small particle size onto g-C3N4, narrow bandgap, large surface area, a rapid transfer of Hg(II) ions and HCOOH to easily reach the active sites due to the facile penetration through the mesostructure, thus promoting the utilization of porous structure of CuO/g-C3N4 heterostructures for efficient diffusion of Hg(II) ions. The intense interaction between mesoporous CuO NPs and porous g-C3N4 confirms the durability of the CuO/g-C3N4 heterostructures during recyclability for five times.

Metal-Free Modified Boron Nitride for Enhanced CO2 Capture

Porous boron nitride is a new class of solid adsorbent with applications in CO2 capture. In order to further enhance the adsorption capacities of materials, new strategies such as porosity tuning, element doping and surface modification have been taken into account. In this work, metal-free modification of porous boron nitride (BN) has been prepared by a structure directing agent via simple heat treatment under N2 flow. We have demonstrated that textural properties of BN play a pivotal role in CO2 adsorption behavior. Therefore, addition of a triblock copolymer surfactant (P123) has been adopted to improve the pore ordering and textural properties of porous BN and its influence on the morphological and structural properties of pristine BN has been characterized. The obtained BN-P123 exhibits a high surface area of 476 m2/g, a large pore volume of 0.83 cm3/g with an abundance of micropores. More importantly, after modification with P123 copolymer, the capacity of pure CO2 on porous BN has improved by about 34.5% compared to pristine BN (2.69 mmol/g for BN-P123 vs. 2.00 mmol/g for pristine BN under ambient condition). The unique characteristics of boron nitride opens up new routes for designing porous BN, which could be employed for optimizing CO2 adsorption.

Kinetics and Energetics of Ultrafast Bimolecular Photoinduced Electron Transfer Reactions in Pluronic-Surfactant Supramolecular Assemblies.

Understanding the kinetics and energetics of photoinduced electron transfer (PET) reactions in constrained media has attracted considerable research interest, as constrained media provide a handle to tune the microenvironments and consequently the mechanisms of PET reactions. In this study, PET reactions between excited 7-aminocoumarin acceptors and ground-state N,N-dimethylaniline (DMAN) donor have been investigated in mixed micellar media composed of triblock copolymer, P123, and anionic surfactant, sodium dodecyl sulfate (SDS), with varying SDS-to-P123 molar ratios (n values). The objective is to elucidate the role of the n values in the rates and energetics of PET reactions over the entire time range from the subpicosecond to the subnanosecond domain, especially in regard to the applicability of the two-dimensional ET (2DET) mechanism. It is observed that by changing the n values, there is a significant change in the hydration characteristics of the SDS-P123 mixed micelles, which in turn changes the kinetics to energetic correlations for the PET reactions. Fluorescence from the excited coumarin acceptors undergoes substantial quenching due to PET from DMAN donor in all of the studied micelles as evidenced from steady-state, subnanosecond time-resolved (TR) and ultrafast (subpicosecond/femtosecond) fluorescence up-conversion measurements. The quenching rate constants (kq), estimated from subnanosecond TR fluorescence studies, and the individual component-wise decay rates (τi-1), estimated from up-conversion measurements, increase gradually with increasing n value, corroborating well with the sequentially increased micropolarity of the mixed micelles. Interestingly, it is observed that the correlations of either kq (from subnanosecond studies) or τi-1 (from femtosecond studies) with the reaction exergonicity (-ΔG°) show the noteworthy Marcus inversion (MI) behavior in a very consistent and similar manner for the entire time window, from subpicoseconds to subnanoseconds. The onset of MI always appears at an exergonicity (-ΔG°MI) much lower than solvent reorganization energy (λs), suggesting the involvement of 2DET mechanism throughout the subpicosecond to subnanosecond time domains. The present results thus provide a comprehensive picture of the kinetics and energetics of the PET reactions in constrained media for the whole time span and unequivocally establish the applicability of 2DET mechanism for the PET reactions in constrained media, eliminating any apprehensions about the effect of time resolution of the subnanosecond setup on the observed Marcus inversion behavior. This is indeed an important finding, providing valuable insights for PET reactions in constrained media, which has not been explored explicitly in any of the previous studies. Observation of MI behavior and the modulations in the PET reactions by simply changing the composition of SDS in the SDS-P123 mixed micelles are noteworthy findings of the present study and are expected to find suitable applications for better utilization and outcome of the PET reactions.

Optical quality mesoporous alumina thin films

Abstract A robust method for the preparation of optical-quality mesoporous alumina thin films is presented, using evaporation induced self assembly of triblock copolymer surfactants. The use of lowly reactive aluminium chloride as a precursor and a tertiary alcohol as a novel chloride scavenger results in highly homogeneous and smooth films with consistent controllable thickness between 30 and 100 nm . The films show very low refractive index and high transparency from UV to NIR regions, providing a new building block for solution processing of devices requiring low-κ materials.