Chemical Surface Functionalization Research Articles

LSPR-susceptible metasurface platform for spectrometer-less and AI-empowered diagnostic biomolecule detection

In response to the growing demand for biomolecular diagnostics, metasurface (MS) platforms based on high-Q resonators have demonstrated their capability to detect analytes with smart data processing and image analysis technologies. However, high-Q resonator meta-atom arrays are highly sensitive to the fabrication process and chemical surface functionalization. Thus, spectrum scanning systems are required to monitor the resonant wavelength changes at every step, from fabrication to practical sensing. In this study, we propose an innovative dielectric resonator-independent MS platform that enables spectrometer-less biomolecule detection using artificial intelligence (AI) at a visible wavelength. Functionalizing the focused vortex MS to capture gold nanoparticle (AuNP)-based sandwich immunoassays causes the resulting vortex beam profiles to be significantly affected by the localized surface plasmon resonance (LSPR) occurring between AuNPs and meta-atoms. The convolutional neural network algorithm was carefully trained to accurately classify the AuNP concentration-dependent focused vortex beam, facilitating the determination of the concentration of the targeted diagnostic biomolecule. Successful in situ identification of various biomolecule concentrations was achieved with over 99 % accuracy, indicating the potential of combining an LSPR-susceptible MS platform and AI for continuously tracking various chemical and biological compounds.

Measurement of Neuropeptides and Amino Acids with Carbon-Fiber Multielectrode Array Enzyme-Modified Biosensors

Carbon fiber microelectrodes (CFMEs) have been used to detect neurotransmitters and other biomolecules using fast-scan cyclic voltammetry (FSCV) for the past few decades. These assays typically measure small molecule neurotransmitters such as dopamine and serotonin. The carbon fiber is relatively small, biocompatible, and makes minimally invasive measurements at high spatial and temporal resolution. Carbon Fiber Multielectrode arrays have been utilized to measure multiple neurotransmitters in several brain regions simultaneously with multi-waveform application on each electrode. We have extended this work to measure larger molecule neuropeptides such as Neuropeptide Y and Oxytocin, a pleiotropic peptide hormone, is physiologically important for adaptation, development, reproduction, and social behavior. This neuropeptide functions as a stress-coping molecule, an anti-inflammatory agent, and serves as an antioxidant with protective effects especially during adversity or trauma. Here, we measure tyrosine using the Modified Sawhorse Waveform (MSW), enabling enhanced electrode sensitivity for the amino acid and peptide, decreased surface fouling, and codetection with other catecholamines. As both oxytocin and Neuropeptide Y contain tyrosine, the MSW was also used to detect these neuropeptides. Additionally, we demonstrate that applying the MSW on CFMEs allows for real time measurements of exogenously applied neuropeptides on rat brain slices. These results may serve as novel assays for neuropeptide detection in a fast, sub-second timescale with possible implications for in vivo measurements and further understanding of the physiological role of neuropeptides such as Neuropeptide Y and oxytocin.Moreover, we have also developed enzyme modified microelectrodes for the measurement of glutamate (L-glutamic acid), which is an important excitatory amino acid and biomarker for epilepsy along with the inhibitory GABA. Since glutamate is not redox active at carbon electrodes, we modified CFMEs with glutamate oxidase enzyme to metabolize glutamate to hydrogen peroxide, which was then oxidized at carbon electrodes to produce readout cyclic voltammograms (CVs). The enzyme coating was optimized by varying the concentration of enzyme, chitosan binder, solvent, and deposition time. The coating was further analyzed electrochemically and imaged with scanning electron microscopy (SEM) for thickness and uniformity of surface coverages. Energy-Dispersive Spectroscopy (EDS/EDX) was utilized for chemical surface functionalization analysis. Glutamate oxidation was found to be adsorption controlled to CFMEs and characterized at various scan rates, concentrations, and stability times as well with an approximate 100 nM limit of detection. Glutamate was co-detected in complex mixtures with several monoamines such as dopamine, serotonin, norepinephrine, and others. Glutamate will furthermore be measured in several food samples and ex vivo in rat coronal brain slices and in vivo in anesthetized and freely behaving animals.

Maintaining the 2D Structure of MXene via Self-Assembled Monolayers for Efficient Lubrication in High Humidity.

MXene is considered as a promising solid lubricant due to facile shearing ability and tuneable surface chemistry. However, it faces challenges in high-humidity environments where excessive water molecules can significantly impact its 2D structure, thus deteriorating its lubricating properties. In this work, the self-assembled monolayers are formed on MXene by surface chlorination (MXene-Cl) and fluorination (MXene-F), and their friction behaviors in high/low humidity are investigated. The results indicate that MXene-F and MXene-Cl can maintain a relatively constant friction coefficient (CoF) (MXene-F ∼0.76, MXene-Cl ∼0.48) under both high (75%) and low (25%)-relative humidity (RH) environments. Meanwhile, the MXene-F and MXene-Cl display a lower CoF than the pristine MXene (MXene CoF∼1.18) in high humidity. The above phenomena are mainly attributed to the preservation of its 2D layered structure, the increased layer spacing, and superficial partial oxidation for SAMs-functionalized MXene under high humidity during friction. Interestingly, MXene-Cl with moderate water resistance has a lower CoF than that of MXene-F with complete water resistance. The nanostructured water adsorption capacity and larger interlayer spacing of MXene-Cl make it exhibit a lower CoF compared to MXene-F. The findings of this study offer valuable guidance for tailoring MXene by surface chemical functionalization as an efficient solid lubricant in high humidity.

Wet chemical surface functionalization of AA2017 powders for additive manufacturing

Laser Powder Bed Fusion (L-PBF) is an important route for processing aluminum alloys, nevertheless, the high laser reflectivity and thermal conductivity and lower powder flowability of the aluminum alloys remain a challenge for their processing. Aiming to overcome these issues, AA2017 powders were surface-functionalized using chemical etchings. The powders' physical and rheological characterization revealed a decrease in the laser reflectance and an improvement in the flowability of the surface-functionalized powders, when compared to the gas-atomized powder. The higher amount of keyhole porosity in the as-printed L-PBF samples using the surface-functionalized powders also suggests an improvement in the laser absorption of these powders. However, the formation of a thick oxide layer on the surface-functionalized powders led to oxidation porosity in the as-printed samples. Therefore, the chemical etching should be improved to avoid the formation of a thick oxide layer on the powder surface and oxidation porosity in the as-printed L-PBF samples.

Photoluminescent carbon nanodots for artificial photosynthesis

The emerging field of carbon dots (CDs), a type of carbon nanostructure that has gained significant attention due to its unique properties and potential applications. CDs possess remarkable attributes, including photoluminescence, electrochemical potential, compatibility with living organisms, solubility in water, chemical stability, and versatile surface properties. The chemical structure, particle size, and surface functionalities of CDs all have an impact on their photoluminescent properties, which are the focus of this review. The photoluminescence mechanism in CDs is discussed, highlighting their amorphous structure, and comparing them to graphene quantum dots. The paper delves into the application of CDs in artificial photosynthesis, which enhances crop growth by improving the photo-synthesis process. CDs increase sunlight and carbon dioxide absorption rates by interacting with plant leaves, potentially leading to substantial crop yield improvements. The advantages of CDs in artificial photosynthesis are explored, including their modifiable absorption characteristics across the ultraviolet to near-infrared spectrum. The paper acknowledges challenges in CD production, such as size control and aggregation, while emphasizing their potential in various fields, including sensing, bioimaging, energy devices, and catalysis. CDs' unique optical properties and versatile applications suggest a promising future for these nanostructures in numerous scientific and technological domains.

Shape Transformation of Polymer Vesicles.

Life activities, such as respiration, are accomplished through the continuous shape modulation of cells, tissues, and organs. Developing smart materials with shape-morphing capability is a pivotal step toward life-like systems and emerging technologies of wearable electronics, soft robotics, and biomimetic actuators. Drawing inspiration from cells, smart vesicular systems have been assembled to mimic the biological shape modulation. This would enable the understanding of cellular shape adaptation and guide the design of smart materials with shape-morphing capability. Polymer vesicles assembled by amphiphilic molecules are an example of remarkable vesicular systems. The chemical versatility, physical stability, and surface functionality promise their application in nanomedicine, nanoreactor, and biomimetic systems. However, it is difficult to drive polymer vesicles away from equilibrium to induce shape transformation due to the unfavorable energy landscapes caused by the low mobility of polymer chains and low permeability of the vesicular membrane. Extensive studies in the past decades have developed various methods including dialysis, chemical addition, temperature variation, polymerization, gas exchange, etc., to drive shape transformation. Polymer vesicles can now be engineered into a variety of nonspherical shapes. Despite the brilliant progress, most of the current studies regarding the shape transformation of polymer vesicles still lie in the trial-and-error stage. It is a grand challenge to predict and program the shape transformations of polymer vesicles. An in-depth understanding of the deformation pathway of polymer vesicles would facilitate the transition from the trial-and-error stage to the computing stage. In this Account, we introduce recent progress in the shape transformation of polymer vesicles. To provide an insightful analysis, the shape transformation of polymer vesicles is divided into basic and coupled deformation. First, we discuss the basic deformation of polymer vesicles with a focus on two deformation pathways: the oblate pathway and the prolate pathway. Strategies used to trigger different deformation pathways are introduced. Second, we discuss the origin of the selectivity of two deformation pathways and the strategies used to control the selectivity. Third, we discuss the coupled deformation of polymer vesicles with a focus on the switch and coupling of two basic deformation pathways. Last, we analyze the challenges and opportunities in the shape transformation of polymer vesicles. We envision that a systematic understanding of the deformation pathway would push the shape transformation of polymer vesicles from the trial-and-error stage to the computing stage. This would enable the prediction of deformation behaviors of nanoparticles in complex environments, like blood and interstitial tissue, and access to advanced architecture desirable for man-made applications.

Promising and Environmentally Friendly Removal of Copper, Zinc, Cadmium, and Lead from Wastewater Using Modified Shrimp-Based Chitosan

This study explores the potential of modified shrimp-based chitosan (MSC) as an innovative adsorbent for eliminating heavy metals (HMs) from contaminated water sources. The modifications encompassed various chemical treatments, surface functionalization, and structural optimization to enhance the chitosan’s adsorption capabilities. Comprehensive analyses using FT-IR and SEM-EDS were conducted to evaluate the properties of the chitosan. The adsorption capacity of MSC was assessed using ICP-MS before and after the adsorption process. Moreover, the study investigated the efficiency of HM removal by MSC under different conditions, including variations in pH, adsorbent dosage, and contact time. Under neutral pH conditions, the highest adsorption rates of copper, zinc, cadmium, and lead were determined as 99.72%, 84.74%, 91.35%, and 99.92%, respectively, with corresponding adsorption capacities of 20.30 mg/g for copper, 7.50 mg/g for zinc, 15.00 mg/g for cadmium, and 76.34 mg/g for lead. Analysis based on the Langmuir and Freundlich isotherm models revealed highly significant adsorption of HMs, supported by strong correlation coefficients (r2 > 0.98) obtained from the data. The pseudo-second-order kinetic model with linear coefficients (r2) greater than 0.97 effectively explained the kinetic studies of metal adsorption employing modified shrimp shells. These coefficients indicate a robust fit of the models to the experimental adsorption data for heavy metals. Further confirmation of the effectiveness of the adsorbent was obtained through FT-IR spectroscopy, which confirmed the presence of specific functional groups on the adsorbent, such as N–H joined with –COO−, H–O, C−O−C, and C–H. Additionally, the SEM-EDS analysis detected the presence of elements on the surface of MSC chitosan. The results emphasize that MSC is a highly effective and cost-efficient adsorbent for eliminating Cu, Zn, Cd, and Pb from wastewater, making it a promising eco-friendly choice.

Impedimetric transduction from a single-step thin film nanoporous aluminum oxide as a DNA sensing electrode

A two-step anodization process has been widely used to grow a perfectly arranged Anodic Aluminum Oxide (AAO) nanoporous with high regularity and circularity. However, this method requires more time and electricity cost since the second step anodization will be conducted more than a couple of hours up to 24 h to obtain a perfect hexagonally arranged AAO. Besides, the usage of toxic chromic acid to remove the rough surface after the first anodization is not recommended. To solve this issue, a single-step of anodization method to grow AAO at 15 °C in 0.3 M of oxalic acid at 40 V for 1 h has been proposed. In this study, the growth AAO thin film will be tested as a DNA biosensor electrode. Prior to that, instead of using toxic chemicals, couple of drops of phosphoric acid solutions were used to treat the rough, uneven surfaces by promoting hydroxyl groups while at the same time widening and revealed the underneath pores. The AAO thin film is ready for the next step of surface modification without a second anodization step. Surface chemical functionalization using 3-aminopropyl-triethoxysilane (APTES) and glutaraldehyde is performed to immobilize the aminated-ssDNA probe on the surface. The electrochemical impedance technique is employed to monitor the changes in each layer of surface modifications. The charged transfer resistance (Rct) values are linearly increased with each new additional layer on the AAO surfaces during each step of surface modification and with the increase in ssDNA complementary target concentrations (10 fM-10 μM). From the performance test, the single-step AAO thin film electrode has shown great results in functioning as a DNA biosensor through a selectivity test. It has the capability to differentiate the complementary sequences from the single mismatched target with 3-fold.

Micromachining on Stainless Steel 304 for Improved Water Condensation Properties

Microstructure fabrication and chemical surface functionalization with low-surface-energy materials are the key steps to achieve hydrophobic surfaces with high water droplet contact angles (CA). In this work we employed wire Electric Discharge Machining (EDM) as a way to induce microstructure topography on stainless steel 304 coupons. The resulting topography was rendered hydrophobic using trichloro-1H,1H,2H,2H-perfluorooctyl silane (PFOTS) via gas phase deposition. The channels created by machining and PFOTS functionalization facilitate water condensation by increasing nucleation sites and enhancing droplet coalescence. The resulting surface is hydrophobic (CA~140o) in contrast to the bare stainless steel 304, which is hydrophilic (CA~76o).

Catch and release: Gold adsorption and sorbent electrochemical regeneration

Wastewater generated from e-waste leaching is rich in precious metals including gold, silver and platinum. Conventional precipitation and solvent extraction are chemically intensive separations with concerning environmental externalities. Sorbents, in particular carbon nanotubes, have low chemical consumption, and have shown promise for gold adsorption due to their high specific surface area and chemical functionalization potential. However, regenerating sorbents used to adsorb Au is hazardous requiring strong acids. Herein, we delineate the effect of various functional groups on the sidewalls of multiwall carbon nanotubes (MWCNTs) on gold adsorption, and we introduced an acid-free electrochemical technique for Au elution from MWCNTs. Pristine MWCNTs (P-MWCNTs), carboxylic functionalised MWCNTs (COOH-MWCNTs) and amide functionalised MWCNTs (NH2-MWCNTs) were compared for their affinity for Au adsorption from acidic AuCl4−solutions mimicking acidic e-waste leachate. Au adsorption affinity onto MWCNTs followed the order of P-MWCNT > NH2-MWCNT > COOH-MWCNTs. Au elution from Au-saturated MWCNTs was subsequently achieved up to 65%, using acid-free electrochemical desorption in neutral aqueous brine. The Au electro-desorption was shown to have a direct relationship with both the applied current and the mass of the Au adsorbed on the MWCNTs. This study demonstrates enhanced adsorption-based preconcentration of gold and acid-free regeneration of sorbents.

Engineering alkaline-stable barley stripe mosaic virus-like particles for efficient surface modification

Viruses and virus-like particles are powerful templates for materials synthesis because of their capacity for precise protein engineering and diverse surface functionalization. We recently developed a recombinant bacterial expression system for the production of barley stripe mosaic virus-like particles (BSMV VLPs). However, the applicability of this biotemplate was limited by low stability in alkaline conditions and a lack of chemical handles for ligand attachment. Here, we identify and validate novel residues in the BSMV Caspar carboxylate clusters that mediate virion disassembly through repulsive interactions at high pH. Point mutations of these residues to create attractive interactions that increase rod length ∼2 fold, with an average rod length of 91 nm under alkaline conditions. To enable diverse chemical surface functionalization, we also introduce reactive lysine residues at the C-terminus of BSMV coat protein, which are presented on the VLP surface. Chemical conjugation reactions with this lysine proceed more quickly under alkaline conditions. Thus, our alkaline-stable VLP mutants are more suitable for rapid surface functionalization of long nanorods. This work validates novel residues involved in BSMV VLP assembly and demonstrates the feasibility of chemical functionalization of BSMV VLPs for the first time, enabling novel biomedical and chemical applications.

Ligand chemistry for surface functionalization in MXenes: A review

AbstractSurface chemistry of MXenes is of significant interest due to its potential to control their final optoelectronic and physicochemical properties, and address the oxidation and dispersion stabilities of MXenes. Surface chemistry of MXenes can be manipulated by either MXene synthesis via chemical etching or post surface functionalization method. Although numerous reviews have explored MXene synthesis methods, there has been a lack of focus on post surface functionalization. This review aims to fill this gap by summarizing recent advancements in the MXene surface functionalization chemistry, and elucidating mechanisms, properties, and future perspectives of functionalized MXenes. We discuss organic ligand molecules, such as organic salts, catechols, phosphonates, carboxylates, and silanes, which can be employed to surface‐functionalize MXene through covalent or non‐covalent bond interaction. This comprehensive review offers valuable insights for scientists and engineers in utilizing functionalized MXenes across diverse applications, including EMI shielding, energy storage, electronics, optoelectronics, and sensors.image

From Whispering Gallery Mode Resonators to Biochemical Sensors.

Optical biosensors are frontrunners for the rapid and real-time detection of analytes, particularly for low concentrations. Among them, whispering gallery mode (WGM) resonators have recently attracted a growing focus due to their robust optomechanical features and high sensitivity, measuring down to single binding events in small volumes. In this review, we provide a broad overview of WGM sensors along with critical advice and additional "tips and tricks" to make them more accessible to both biochemical and optical communities. Their structures, fabrication methods, materials, and surface functionalization chemistries are discussed. We propose this reflection under a pedagogical approach to describe and explain these biochemical sensors with a particular focus on the most recent achievements in the field. In addition to highlighting the advantages of WGM sensors, we also discuss and suggest strategies to overcome their current limitations, leaving room for further development as practical tools in various applications. We aim to provide new insights and combine different knowledge and perspectives to advance the development of the next generation of WGM biosensors. With their unique advantages and compatibility with different sensing modalities, these biosensors have the potential to become major game changers for biomedical and environmental monitoring, among many other relevant target applications.

A method for multiplexed and volumetric-based magnetic particle spectroscopy bioassay: mathematical study

Magnetic particle spectroscopy (MPS) is an emerging biosensing technique that detects target analytes by exploiting the dynamic magnetic responses of magnetic nanoparticles (MNPs). Due to the ease of synthesis and surface chemical functionalization of MNPs, MPS-based bioassays have gained popularity around the globe. One limiting factor for MPS-based assay is the ability to detect multiple analytes simultaneously in a single run, namely, multiplexed bioassay. Several groups have reported the realization of multiplexed bioassays on surface-based MPS platforms by spatially separating reaction areas by using the unique magnetic responses of different MNPs. In this work, we systematically study the magnetization curves (M-H curves) of different types of MNPs and their relationship to the dynamic magnetic responses when subjected to AC magnetic driving fields. Due to the different structures, sizes, and magnetic properties of each kind of MNP, the resulting harmonics are unique. Thus, concurrent quantification (also called ‘colorization’) of each type of MNP in a mixture is possible by solving the harmonic matrix function. Our results show that the uniqueness of M-H response curves of selected types of MNP and the signal-to-noise ratio of the system can affect the accuracy of multiplexed, volumetric-based MPS bioassays. The reported method assumes that each type of MNPs nanoparticles does not interact, and that the magnetic response of the mixture is a linear combination of the responses of each kind of MNP. This assumption may not hold for very dense systems where inter-particle interactions become significant and may require more complex models.

Thermal Conductivity of a Two-Dimensional Diamondene Sheet: A Molecular Study

Diamondene, as a novel two-dimensional layered material, exhibits a high carrier mobility resembling those of diamond thin films and holds great promise in electronic devices, while its thermal properties are yet to be investigated. In this paper, the thermal behaviors of diamondene are investigated using molecular dynamic simulation, and the effects of orientation, temperature, hydrogenation, and defect on the thermal conductivity are considered. At simulated temperatures of 300 K, for diamondene, the thermal conductivities of the armchair direction consist of with that of the zigzag direction. The thermal conductivity of quantum correction is reduced to 89% of the classical MD results. The thermal conductivity is sensitive to strain engineering but almost independent of surface chemical functionalization. Thermal conductivity decreases with defect concentration and then enhances (stable stage at a defect concentration range of 20 and 80%). The phenomena are explained by phonon-density-state and micro-heat-flux scatting. It is attributed to the interplay between two cooperating/competing mechanisms of phonon and the compressive effect of the scatted phonon at different chirality. Our study offers a fundamental understanding of thermal transport in diamondene, which will enrich the studies of 2D materials in the field of thermal transfer.

Triboelectric charge modulation to understand the electrification process in nanogenerators combined with an efficient power management system for IoT applications

Mechanical energy harvesting from ambient environment has been considered one of the promising technologies for developing autonomous self-powering units, sensors, and various other electronic applications. Triboelectric nanogenerators (TENGs) are one of the recent technologies gaining tremendous interest because of their ability to efficiently harvest ambient energy and convert it into electricity. The phenomenon of the triboelectrification effect in TENGs is not fully understood, along with extracting a maximum electrical output. Herein, we studied the electrification process between two triboelectric films by modulating their charge polarity. The charge polarity in the triboelectric film was modulated without any surface chemical functionalization. A TENG was fabricated to experimentally study the electrification process. Initially, the accepting/donating electrons of a triboelectric film were modulated using fluorine and oxygen atoms contained in polymers and operated against an oppositely charged triboelectric film. After optimizing the electrical output and conducting various stability investigations, the electrical output from the TENG was enhanced. Ultra-low power management integrated circuit (PMIC) implemented in a 180 nm high-voltage BCD (Bipolar CMOS DMOS) process was used. While matching the effective impedance of the TENGs, the PMIC achieves a total energy transfer efficiency of 81.5% utilizing a relatively low input power of 6.5 µW, showing state-of-the-art performance.

An efficient designing of nitrogen decorated carbon quantum dots as Fe fluorescent probe: On account of binary carbon source system

Accurate detection of Fe3+ is an urgent need due rapid increase of hemochromatosis, methemoglobinemia, mental decline and physical weakness throughout the world. Here, nitrogen-doped carbon quantum dots (NCQDs) having blue fluorescence were prepared by facile one-spot hydrothermal method by using binary carbon source. This innovative primed hybrid NCQDs were well characterized by using FT-IR, XPS, and EDS and SEM for purpose of chemical composition and surface functionality. The morphology of NCQDs were confirmed their spherical shape and an average diameter was 4.3 nm by TEM measurement. Surface coating for functional group and nitrogen doped was monitored by the FTIR, XPS and EDX analysis. The photoluminescence measurements showed that NCQDs were non-wavelength dependent with a quantum yield of 73.89%. The NCQDs showed strong evidence to be a excellent fluorescent sensor for the rapid and quick estimation of Fe3+ with high selectivity and sensitivity. The fluorescence power of NCQDs were slowly declined with higher amount of Fe3+ concentration ranging from 0.01 to 0.5 and 1–33.3 μM. The accurate range of detection limit was very narrow and found to be 5 nM for Fe3+by this method. Furthermore, the function of novel NCQDs for estimation of trace element such as Fe3+ in different sources of water was yielded at very acceptable recoveries (97.30% ∼ 98.04%). The current designed functional probe provided a promising fluorescent range at narrow level for the Fe3+ detection is highly appreciable in the future studies.

Superhydrophobic and oleophobic microtextured aluminum surface with long durability under corrosive environment

Superhydrophobic (SHP) and oleophobic aluminum surfaces have been prepared through the combination of a scalable chemical microtexturing process and surface functionalization with long-chained polyfluoroalkyl moieties. The effect of an anodic layer on the microtextured surface has been assessed considering surface morphology, superhydrophobicity, surface mechanical properties and corrosion protection enhancement. The surface functionalization with polyfluoroalkyl moieties has been tackled in two different ways: (i) grafting of the polyfluoroalkyl moieties and (ii) deposition of a thin hybrid coating with low content of polyfluoroalkyl-containing compound. Aluminum surfaces showing high durability in salt spray environments, which maintain SHP and oleophobic properties at least up to 2016 h have been attained. Applications for this kind of surfaces range from easy-to-clean surfaces to anti-icing or anti-condensation functionalities that could be of interest for several sectors.

The heteroaggregation behavior of nanoplastics on goethite: Effects of surface functionalization and solution chemistry

Nanoplastics have attracted extensive attention in recent years. However, little is known about the heteroaggregation behavior of nanoplastics on goethite (FeOOH), especially the contribution of surface functional groups. In this study, the heteroaggregation behavior between polystyrene nanoplastics (PSNPs) and FeOOH was systematically investigated under different reaction conditions. Moreover, the effect of different functional groups (-NH2, -COOH, and bare) of PSNPs and solution chemistry was evaluated. The results showed that PSNPs could heteroaggregate with FeOOH, and the heteroaggregation rate of PSNPs with surface functionalization was significantly faster. The removal of suspended PSNPs was enhanced with increasing NaCl or CaCl2 concentration. However, heteroaggregation was significantly inhibited with the increase of solution pH. The zeta potentials analysis, time-resolved dynamic light scattering (DLS) and heteroaggregation experiments suggested that the electrostatic force affected the heteroaggregation process significantly. Fourier transform infrared (FTIR) spectra proved that the adsorption affinity between PSNPs and FeOOH was stronger after surface functionalization, especially for CH, O-C=O, and -CH2- groups, indicating that chemical bonding also made a contribution during the heteroaggregation process. This work is expected to provide a theoretical basis for predicting the environmental behavior between PSNPs and FeOOH.

Anti-icing solutions combining printed electronics and nanotexturing of Al alloys

Aluminum superhydrophobic (SHP) surfaces have been prepared by the combination of chemical microtexturing and surface functionalization with long-chained polyfluoroalkyl moieties. On the opposite side to the modified surface self-limiting heating element has been printed using carbon based possitive temperature coefficient (PTC) inks. Different heater configurations were tested to optimize heater design. Results showed that the combination of both strategies was able to maintain the aluminum surface ice free under tested conditions. The developed hybrid system showed good performance under anti-icing conditions with potential to be applied in aircraft systems.