The effect of particle loading on the wetting properties of coatings was investigated by modifying a coating formulation based on hydrophilic silica nanoparticles and poly (acrylic acid) (PAA). Water contact angle (WCA) measurements were conducted for all coatings to characterize the surface wetting properties. Wettability was improved with an increase in particle loading. The resulting coatings showed superhydrophilic (SH) behavior when the particle loading was above 53 vol. %. No new peaks were detected by attenuated total reflection (ATR-FTIR). The surface topography of the coatings was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The presence of hydrophilic functional groups and nano-scale roughness were found to be responsible for superhydrophilic behavior. The surface chemistry was found to be a primary factor determining the wetting properties of the coatings. Adhesion of the coatings to the substrate was tested by tape test and found to be durable. The antifogging properties of the coatings were evaluated by exposing the films under different environmental conditions. The SH coatings showed anti-fogging behavior. The transparency of the coatings was significantly improved with the increase in particle loading. The coatings showed good transparency (>85% transmission) when the particle loading was above 84 vol. %.

Superhydrophilic coatings based on a hydrophilic silica nanoparticle suspension and Poly (acrylic acid) (PAA) were prepared by dip coating. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) were used to examine the morphology of the coating. The effect of surface morphology on the dynamic wetting behavior of the superhydrophilic coatings was studied by changing the silica suspension concentration from 0.5% wt. to 3.2% wt. while keeping the silica concentration in the dry coating constant. The droplet base diameter and dynamic contact angle with respect to time were measured using a high-speed camera. A power law was found to describe the relationship between the droplet diameter and time. A significantly low experimental power law index was obtained for all the coatings. Both roughness and volume loss during spreading were suggested to be responsible for the low index values. The water adsorption of the coatings was found to be the reason for the volume loss during spreading. The coatings exhibited good adherence to the substrates and retention of hydrophilic properties under mild abrasion.

In this study, particle loading, polyfluorinated alkyl silanes (PFAS or FAS) content, superhydrophobicity, and crack formation for nanocomposite coatings created by the spray coating process were investigated. The formulations comprised hydrophobic silica, epoxy resin, and fluorine-free or FAS constituents. The effect of FAS content and FAS-free compositions on the silica and epoxy coatings’ chemistry, topography, and wetting properties was also studied. All higher particle loadings (~30 wt.%) showed superhydrophobicity, while lower particle loading formulations did not show superhydrophobic behavior until 13% wt. FAS content. The improved water repellency of coatings with increased FAS (low particle loadings) was attributed to a combination of chemistry and topography as described by the Cassie state. X-ray photoelectron spectroscopy (XPS) spectra showed fluorine enrichment on the coating surface, which increases the intrinsic contact angle. However, increasing the wt.% of FAS in the final coating resulted in severe crack formation for higher particle loadings (~30 wt.%). The results show that fluorine-free and crack-free coatings exhibiting superhydrophobicity can be created.

A novel approach for synthesizing polymer particles that encapsulate Fe₃O₄ nanoparticles using γ-ray irradiated mini-emulsion polymerization is presented. To achieve high encapsulation efficiency, the surface properties of Fe₃O₄ nanoparticles are modified from hydrophilic to hydrophobic, allowing for effective dispersion in the monomer prior to polymerization. Mini-emulsion techniques have proven essential for forming the encapsulated structure and controlling particle size distribution. γ-ray irradiation initiated radical polymerization and solidified the emulsion structure. Characterization via FTIR, XRD, and TEM confirmed the successful encapsulation of Fe₃O₄ nanoparticles within polymer particles. Magnetic measurements demonstrated superparamagnetic behavior and high magnetic induction, both of which are properties considered advantageous for biomedical applications.

A comprehensive study was conducted to develop structurally robust, crack-suppressed superhydrophilic nanocomposite coatings comprising poly(acrylic acid) (PAA) and silica nanoparticles. We systematically investigated the critical trade-off between particle loading, which drives surface wettability and stress-induced crack formation driven by capillary forces and shrinkage mismatch. Our findings identify a distinct structural failure threshold between 25 and 30 vol.% silica under conventional drying. By strategically optimizing drying kinetics (an initial flash-dry at 120 °C for 1 h followed by a 24 h ambient cure), we successfully fabricated transparent, crack-suppressed superhydrophilic coatings at elevated silica loadings up to 47 vol.%, establishing a practical, scalable framework for advanced functional surface engineering. The crack-suppressed mechanism was hypothesized to be related to internal stress.

This study investigates the influence of PFAS-free superhydrophobic treatment on the performance of NYCO (50% Nylon 50% Cotton) fabric. The primary focus is to assess how these treatments influence key performance attributes, including water repellency, weight gain, air permeability, and color stability. The treatments were formulated using a silica/epoxy diluted with isopropanol (IPA), with the goal of achieving minimal weight gain (<10%) and high water repellency (AATCC22 rating of 80 or above) with a minimal impact on breathability and visual appearance. A series of formulations were prepared with a a constant silica to epoxy ratio (3:7) while varying the solids content of the suspension (1.8 to 5.2 wt.%). Treated fabrics were evaluated through water spray tests (AATCC TM 22), air permeability (ASTM D737), spectrophotometric color analysis, and SEM surface morphology. Samples treated with a formulation containing 2.0 wt.% solids content demonstrated the best performance characteristics: low weight gain, minimal breathability reduction, low color change, and water repellency. The findings reveal the potential for a PFAS-free treatment to achieve high water repellency while maintaining other key fabric performance characteristics. The results contribute to the advancement of sustainable, high-performance protective textiles for military applications.