Erfan Kimiaei

The textile industry is striving to develop versatile coatings, combining antibacterial, water-repellent, and breathable properties, all while avoiding toxic components. However, the current solutions have unfavorable ecological impacts. Although the use of waxes has offered promise and is an eco-friendly option, there remains a challenge in achieving all the desired properties in a single solution. Here, we employed biobased nanoparticles, produced from natural fatty acid, tall oil fatty acid… Show more

The textile industry is striving to develop versatile coatings, combining antibacterial, water-repellent, and breathable properties, all while avoiding toxic components. However, the current solutions have unfavorable ecological impacts. Although the use of waxes has offered promise and is an eco-friendly option, there remains a challenge in achieving all the desired properties in a single solution. Here, we employed biobased nanoparticles, produced from natural fatty acid, tall oil fatty acid (TOFA) and lauric acid (La) esterified lignins and waxes, to create multifaceted textile coatings using a layer-by-layer deposition method. Our results reveal that even at nanoscale thickness, the developed coatings enhanced the water contact angle (WCA) of fabrics from 43° to ∼150° while maintaining good breathability (air permeability ranging between 23 and 31 mm/s. Moreover, the coated fabrics maintained excellent hydrophobicity even after two washing cycles. The surface morphology and roughness of the coatings characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed a defect-free and integrated coating layer. Additionally, the polyaromatic molecules integrated into the coatings contributed to the textiles’ antibacterial properties against S. aureus (∼50% inhibition rate) and improved UV-shielding properties, demonstrating the potential for tailored functionality based on specific application requirements. Our systematic correlation of chemical structure and particle properties enabled a comprehensive understanding of their influence on the functionality and performance of coated fabrics. Furthermore, the layer-by-layer method utilizing biobased particles is a simple and efficient method to enhance the performance of cellulose-based materials. This positions the approach as a promising solution for widespread multifunctional textile applications, such as outdoor clothing. Show less

Pickering particles play an essential role in stabilizing Pickering foams that can be utilized as templates for making lightweight porous materials for thermal insulation purposes. With the shift from petroleum to renewable-source-derived materials, particles synthesized from biomass are emerging but are typically too hydrophilic to function as Pickering particles in foams. Here, we report the hydrophobization of lignin nanoparticles (LNPs) by adsorption of an oppositely charged surfactant for… Show more

Pickering particles play an essential role in stabilizing Pickering foams that can be utilized as templates for making lightweight porous materials for thermal insulation purposes. With the shift from petroleum to renewable-source-derived materials, particles synthesized from biomass are emerging but are typically too hydrophilic to function as Pickering particles in foams. Here, we report the hydrophobization of lignin nanoparticles (LNPs) by adsorption of an oppositely charged surfactant for air-in-water Pickering foam stabilization. The surface tension and complex viscoelasticity of the aqueous dispersions were tunable by varying the concentration of LNPs and the adsorption ratio of hexadecyltrimethylammonium bromide (CTAB) onto LNPs, which were systematically studied with the pendant drop technique (DPT). Under the optimum conditions, the achieved air-in-water Pickering foams were remarkably stable against coalescence and coarsening, i.e., the bubble size distribution remained unchanged over 30 days. We further utilized the Pickering foams as templates for making dry lightweight composite foams with the introduction of cellulose nanofibrils (CNFs). The closed-cell composite foams, with lignin as the major component, exhibited good thermal insulation properties and mechanical properties that were comparable to commercial rigid polyurethane (PU) foams. We envision that the renewable Pickering particles could find applications in many other areas beyond the templates for porous materials such as enhanced oil recovery. Show less

Developing biodegradable material alternatives is crucial to address the fossil-based plastic pollution in marine ecosystems. Natural biodegradable polymers like cellulose exhibit potential plastic alternatives. However, their susceptibility to water and moisture poses challenges when blending with hydrophobic polymers. Thus, chemical modification is often required to enhance cellulose dispersion in hydrophobic polymer matrices, which may hinder its inherent biodegradability. In this study, the… Show more

Developing biodegradable material alternatives is crucial to address the fossil-based plastic pollution in marine ecosystems. Natural biodegradable polymers like cellulose exhibit potential plastic alternatives. However, their susceptibility to water and moisture poses challenges when blending with hydrophobic polymers. Thus, chemical modification is often required to enhance cellulose dispersion in hydrophobic polymer matrices, which may hinder its inherent biodegradability. In this study, the aquatic biodegradation and degradation mechanisms of lignocellulose-polyester composite films under aerobic conditions were for the first time explored in simulated freshwater and real seawater environments. The composite films were produced by blending cellulose nanofibrils (CNFs) with polycaprolactone (PCL), a hydrophobic polyester, using lignin nanoparticles (LNPs) as an interfacial compatibilizer. The structural and morphological changes of the composite films were studied using Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Despite the use of LNPs (poorly degradable in aquatic conditions) and the composite films’ hydrophobicity, the presence of up to 25 wt% PCL and 5wt% LNPs did not prevent the composites from achieving > 85% biodegradation within 42 days, in both fresh water and seawater conditions. The incorporation of CNFs increased the water uptake capability of PCL which helped to increase the films’ porosity, in turn enhancing the film degradation process. This study confirmed that hydrophobizing nanocellulose with biodegradable polyesters and LNPs can preserve the nanocellulose’s inherent coveted biodegradability. Hence, this sustainable approach to developing bio-based composites supports responsible material development, disposal, and end-of-life management. Show less

Free-standing nanocellulosic films (nanopapers) emerge as attractive sustainable materials to replace traditional plastics. However, the moisture sensitivity of cellulose and its poor dispersion in hydrophobic polymers are challenges to its widespread application. Harnessing the inherent properties of cellulose, lignin, and polycaprolactone, a Pickering emulsion approach is proposed to produce multifunctional cellulose nanofibril (CNF) nanocomposite films. Aqueous CNF dispersion is combined… Show more

Free-standing nanocellulosic films (nanopapers) emerge as attractive sustainable materials to replace traditional plastics. However, the moisture sensitivity of cellulose and its poor dispersion in hydrophobic polymers are challenges to its widespread application. Harnessing the inherent properties of cellulose, lignin, and polycaprolactone, a Pickering emulsion approach is proposed to produce multifunctional cellulose nanofibril (CNF) nanocomposite films. Aqueous CNF dispersion is combined with hydrophobic polycaprolactone (PCL) using colloidal lignin nanoparticles (CLPs) as the emulsion stabilizer. CNF–PCL nanocomposite films with over 134% increase in dry strength compared to nanocomposites without CLPs are fabricated. This interfacial engineering strategy results in a CNF-based nanocomposite with wet strength up to 87 MPa without any chemical modification or crosslinking agents. The mechanism behind the achieved excellent dry and wet strength and water resistance is investigated and it is suggested that it is due to the amphiphilic CLPs that are able to form non-covalent bonds with both cellulose and PCL, thus binding these together. Furthermore, the nanocomposite films’ protection against UV and oxidation is significantly enhanced by increasing the CLPs content. Our proposed interfacial engineering strategy can be generically applied to other polymer systems and shows a great potential to pave the way toward replacing fossil-based plastics. Show less

The current study provides a comprehensive rheology study and a survey on direct ink writing of xanthan gum/cellulose nanocrystal (XG/CNC) bio-inks for developing 3D geometries that mimic soft tissue engineering scaffolds' physical and mechanical properties. The presence of CNC was found to be a critical prerequisite for the printability of XG bio-inks; accordingly, the hybrid XG/CNC bio-inks revealed the excellent viscoelastic properties that enabled precise control of hydrogel shaping and… Show more

The current study provides a comprehensive rheology study and a survey on direct ink writing of xanthan gum/cellulose nanocrystal (XG/CNC) bio-inks for developing 3D geometries that mimic soft tissue engineering scaffolds' physical and mechanical properties. The presence of CNC was found to be a critical prerequisite for the printability of XG bio-inks; accordingly, the hybrid XG/CNC bio-inks revealed the excellent viscoelastic properties that enabled precise control of hydrogel shaping and printing of lattice structures composed of up to eleven layers with high fidelity and fair resolution without any deformation after printing. The lyophilized 3D scaffolds presented a porous structure with open and interconnected pores and a porosity higher than 70%, vital features for tissue engineering scaffolds. Moreover, they showed a relatively high swelling of approximately 11 g/g, facilitating oxygen and nutrient exchange. Furthermore, the elastic and compressive moduli of the scaffolds that enhanced significantly upon increasing CNC content were in the range of a few kPa, similar to soft tissues. Finally, no significant cell cytotoxicity was observed against human liver cancer cells (HepG2), highlighting the potential of these developed 3D printed scaffolds for soft tissue engineering applications. Show less

Plant-based hydrogels have attracted great attention in biomedical fields since they are biocompatible and based on natural, sustainable, cost-effective, and widely accessible sources. Here, we introduced new viscoelastic bio-inks composed of quince seed mucilage and cellulose nanofibrils (QSM/CNF) easily extruded into 3D lattice structures through direct ink writing in ambient conditions. The QSM/CNF inks enabled precise control on printing fidelity where CNF endowed objects with shape… Show more

Plant-based hydrogels have attracted great attention in biomedical fields since they are biocompatible and based on natural, sustainable, cost-effective, and widely accessible sources. Here, we introduced new viscoelastic bio-inks composed of quince seed mucilage and cellulose nanofibrils (QSM/CNF) easily extruded into 3D lattice structures through direct ink writing in ambient conditions. The QSM/CNF inks enabled precise control on printing fidelity where CNF endowed objects with shape stability after freeze-drying and with suitable porosity, water uptake capacity, and mechanical strength. The compressive and elastic moduli of samples produced at the highest CNF content were both increased by ~100% (from 5.1 ± 0.2 kPa and 32 ± 1 kPa to 10.7 ± 0.5 and 64 ± 2 kPa, respectively). These values ideally matched those reported for soft tissues; accordingly, the cell compatibility of the printed samples was evaluated against HepG2 cells (human liver cancer). The results confirmed the 3D hydrogels as being non-cytotoxic and suitable to support attachment, survival, and proliferation of the cells. All in all, the newly developed inks allowed sustainable 3D bio-hydrogels fitting the requirements as scaffolds for soft tissue engineering. Show less

A new fluorescent tetra-stilbene compound, 1,4-bis-dodecyloxy-2,5-bis-(2-{4-[2-(4-methanesulfonyl-phenyl)-vinyl]-phenyl}-vinyl)-benzene (BDSSTS) derived from Heck chemistry was successfully synthesized. The Pd-catalyzed Heck reaction was used as the key synthetic stage to couple styrene unites with aryl halides. The BDSSTS material is an acceptor-pi-acceptor (A-pi-A) conjugated system with alkoxy chain in central and sulfonyl groups in terminals of the molecule. The BDSSTS compound showed… Show more

A new fluorescent tetra-stilbene compound, 1,4-bis-dodecyloxy-2,5-bis-(2-{4-[2-(4-methanesulfonyl-phenyl)-vinyl]-phenyl}-vinyl)-benzene (BDSSTS) derived from Heck chemistry was successfully synthesized. The Pd-catalyzed Heck reaction was used as the key synthetic stage to couple styrene unites with aryl halides. The BDSSTS material is an acceptor-pi-acceptor (A-pi-A) conjugated system with alkoxy chain in central and sulfonyl groups in terminals of the molecule. The BDSSTS compound showed UV–vis absorption in the range of 423–426 nm with high molar extinction coefficients (ε = 1.9–9.1 × 104 M−1.cm−1) in tested solvents. This new fluorescent compound emits in the yellow region of the visible spectrum (500–525 nm) with Stokes shifts of 3641–4429 cm−1. The geometry optimization calculations were performed with the use of DFT method applying B3LYP functional and 6–311++G (d, p) basis set. Low total Lewis and HOMO-LUMO gap are followed by significant charge transfers, absorption, and emission in the BDSSTS structure. Show less