Deposition Of Tannic Acid Research Articles

Functionalized expanded graphite foam supported by PVDF skeleton for cationic dyes selectively separating and purifying

In order to fully utilize the advantages of expandable graphite (large specific surface area and porous structure), a solvent-free method was used to provide a supporting skeleton for expandable graphite through melting, bonding and solidification of polyvinylidene fluoride (PVDF). Based on its porous structure and enhanced mechanical stability, the formed PVDF/expandable graphite composite foam, amounts of functional groups were introduced throughout the foam (outside on the surface and inner side in the expandable graphite) by deposition of tannic acid (TA) and dopamine (DA), endowing it selective adsorption characteristics. The functioned foam exhibited excellent dynamic dye adsorption capacity by capturing dye molecules firmly through π-π interaction, hydrogen bonding, and charge attraction between the functional groups and dyes. Furthermore, with low zeta potential (-24.9 mV), the functional groups showed selective adsorption properties resulting in rapid separation of cationic dyes and anionic dyes. The functionalized PVDF/expandable graphite composite foam contact these two materials together in order to complement each other's advantages, showing a new research orientation for the treatment of different types of dyestuff wastewater.

Enhancing permeability and mechanical properties of rubber cement-based materials through surface modification of waste tire rubber powder

In this study, the authors present a detailed investigation into the surface mineralization of recycled rubber powder (RP) to enhance its performance in cement mortars. A modified rubber, referred to as RTC, is produced by employing a straightforward and efficient method involving the deposition of tannic acid (TA) and calcium carbonate (CaCO3, <5 μm) on the surface of RP. The main objective of this research is to elucidate the impact of RTC on the impermeability, mechanical properties, and pore structure of rubberized mortar. Through a comprehensive set of characterizations and tests, we demonstrate the successful deposition of TA and CaCO3 on the RP surface, resulting in RTC with excellent chemical activity and hydrophilicity, while also providing nucleation sites for hydration products. This modification process facilitated improved interfacial affinity with cement paste, enhancing bonding between rubber and cement paste. Remarkably, the incorporation of rubber into mortars with markedly enhanced resistance to permeation, with RTC mortars demonstrating particularly noticeable improvement. The marginal decrease in density in comparison to conventional mortars arises from the rubber's lightweight properties. Moreover, rubber exerts a minor adverse influence on hydration kinetics, yet this detrimental impact is alleviated in mortars incorporating RTC. Notably, the study elucidates the nuanced changes in porosity induced by rubber incorporation, underscoring its influence on the mechanical performance of rubberized cement mortars. The RTC5 mortar with a 5% content demonstrates the most remarkable enhancement compared to RP5 mortar. Overall, this study highlights the potential of surface mineralization of RP as a promising approach for improving the performance of rubberized cement mortars.

Insight into the enhanced interfacial adhesion of carbon fiber reinforced composites: A facile ferric ion and tannic acid self-assembly strategy

Applications of carbon fiber reinforced polymer composites are subjected the poor interfacial adhesion due to the smooth and chemically inert of CF surface. In this work, we proposed an effective and simple approach to improve the interfacial properties between CF and matrix by self-assembling the ferric ion (Fe3+) and tannic acid (TA) on the carbon fiber surface within minutes. TA can rapidly coordinate with Fe3+ ions into three-dimensional Fe3+-TA complex networks, the morphologies of which were controlled by Fe3+/TA molar ratio and deposition cycles, which played a key role in the interfacial performance. As Fe3+/TA molar ratio is optimized to 4, Fe3+-TA complex aggregated to nano-sized bulges on the fiber surface, affording numerous mechanical interlocking points which can promote the stress transfer from matrix to fiber and induce the deflection of cracks. Moreover, breaking metal–ligand coordination bonds of Fe3+-TA complex as cracks propagate can dissipate lots of fracture energy, leading to the interfacial shear strength of Fe3+-TA complex modified CF/epoxy vinyl resin composites being improved by ∼ 80 % as compared with the pristine sample. This strategy is facile, mild, and eco-friendly, which opens a feasible avenue for enhancing the interfacial adhesion of CFRPs.

Osmotically assisted solvent reverse osmosis membrane for dewatering of aqueous ethanol solution

To meet the demand of ethanol, researchers are encouraged to develop sustainable membrane processes for solvent recovery. Osmotically assisted reverse osmosis (OARO) process, a new membrane technology, shows a promising alternative for desalination; but it has never been applied in solvent recovery because OARO membranes have relatively larger pore sizes than the molecular sizes of solvents. Therefore, the traditional RO membranes require further modification to separate water from ethanol. Two simple approaches are considered in this work: (1) heat treatment of commercial RO membrane to reduce the pore size of the selective polyamide layer and (2) deposition of tannic acid (TA)-polyethyleneimine (PEI) complex to boost the affinity of the membrane with water molecules. The modified RO membrane achieves over 95% rejection of ethanol, as well as highly efficient recovery of ethanol during osmotically assisted solvent reverse osmosis (OASRO). Furthermore, molecular dynamic simulation elucidated the underlying mechanisms of the effects of annealing and coating on membrane pore size and surface affinity to water/ethanol molecules, respectively. This work opens an opportunity for further development of a more efficient and effective solvent purification process.

Tannic acid (TA)-based coating modified membrane enhanced by successive inkjet printing of Fe3+ and sodium periodate (SP) for efficient oil-water separation

Wettability of membrane is of vital importance for treatment of oily wastewater. In recent years, hydrophilic modifications based on plant polyphenol have been widely investigated to enhance the anti-fouling property of membranes due to their mild conditions, versatility and low cost. However, there are still some problems in improving raw material utilization and hydrophilicity. Herein, a facile method was proposed to optimize tannic acid (TA)-based membrane modification process by synergistically inducing TA deposition by Fe3+ and SP with the assistance of inkjet printing. The hydrophobicity of polyvinylidene fluoride (PVDF) membrane was converted to hydrophilicity (WCA = 34.6°) and underwater oleophobicity (UOCA = 144.4°) in very short time (10 min). The optimum PVDF/Fe-TA-SP422 membrane possessed high flux (4968.4–7340.4 L m−2 h−1·bar−1) for a number of oil/water emulsions with high separation efficiency (>98%), outperforming most state-of-the-art membranes for oil-water separation. Furthermore, the optimized membrane displayed not only high antifouling property and reusability with flux recovery ratio of 89.1%–98.0% after eight-cycle filtration, but also desired stability under near neutral pH conditions during long-term running. The combination of inkjet printing method with these materials proposed in this study is convenient, efficient and low cost, and the prepared membranes are versatility, providing novel insights into preparation of high efficiency membranes for oily wastewater treatment.

A greener approach to design Janus PVDF membrane with polyphenols using one-pot fabrication for emulsion separation

In contrast to the traditional coating of tannic acid (TA), the deposition of mussel-inspired TA on hydrophobic PVDF surfaces is realized using a one-pot fabrication method, thus forming a multi-functional Janus membrane. In this study, a facile TA modification using vacuum filtration is demonstrated to modulate the wettability of PVDF on a single side. With the introduction of sodium periodate, rapid chemical oxidation of TA occurs, which results in the design of a thin hydrophilic coverage over one side of the PVDF membrane. This multi-functional Janus membrane demonstrates a higher separation efficiency of ∼ 99% and ∼ 97% for both oil-in-water and water-in-oil emulsions. The hydrophilic coating of the Janus PVDF-TA membrane remains stable in harsh environments. Moreover, the recyclability of the as-prepared membrane evidenced an oil rejection performance of 99% for three repeating cycles. This nature-inspired Janus membrane using a green modification method is new insights for integrating the area of bionics into oily wastewater treatment.

Endowing Orthopedic Implants' Antibacterial, Antioxidation, and Osteogenesis Properties Through a Composite Coating of Nano-Hydroxyapatite, Tannic Acid, and Lysozyme.

There is a substantial global market for orthopedic implants, but these implants still face the problem of a high failure rate in the short and long term after implantation due to the complex physiological conditions in the body. The use of multifunctional coatings on orthopedic implants has been proposed as an effective way to overcome a range of difficulties. Here, a multifunctional (TA@HA/Lys)n coating composed of tannic acid (TA), hydroxyapatite (HA), and lysozyme (Lys) was fabricated in a layer-by-layer (LBL) manner, where TA deposited onto HA firmly stuck Lys and HA together. The deposition of TA onto HA, the growth of (TA@HA/Lys)n, and multiple related biofunctionalities were thoroughly investigated. Our data demonstrated that such a hybrid coating displayed antibacterial and antioxidant effects, and also facilitated the rapid attachment of cells [both mouse embryo osteoblast precursor cells (MC3T3-E1) and dental pulp stem cells (DPSCs)] in the early stage and their proliferation over a long period. This accelerated osteogenesis in vitro and promoted bone formation in vivo. We believe that our findings and the developed strategy here could pave the way for multifunctional coatings not only on orthopedic implants, but also for additional applications in catalysts, sensors, tissue engineering, etc.

Simultaneous deposition of tannic acid and poly(ethylene glycol) to construct the antifouling polymeric coating on Titanium surface

Titanium (Ti) and its alloys are primarily explored to produce biomedical implants owing to their improved mechanical stability, corrosion resistance, low density, and good biocompatibility. Despite, Ti substrate surfaces are easily contaminated by plasma proteins and bacteria. Herein, a simple one-step process for the simultaneous deposition of a polyphenol tannic acid (TA) and four-armed poly(ethylene glycol) (PEG10k-4−OH) on the Ti substrate (Ti-TA/PEG) surface was described. Additionally, a two-step process has been employed to fabricate the Ti-TA-PEG surface via successive deposition of TA and PEG10k-4−OH for comparison. The resultant Ti-TA/PEG surface prepared by simultaneous deposition of TA and PEG10k-4−OH exhibits higher coating thickness and better surface coverage than the Ti-TA-PEG surface. The Ti-TA/PEG and Ti-TA-PEG surfaces could actively inhibit the non-specific adsorption of proteins, suppress the bacterial and platelet adhesion, and prevents biofilm formation. Moreover, the Ti-TA/PEG surface displays a better antifouling performance than the Ti-TA-PEG surface. Thus, the present study demonstrates a simple and convenient approach for constructing polymeric coating with good anti-adhesive properties on the Ti substrate surface.

One-step modification of PVDF membrane with tannin-inspired highly hydrophilic and underwater superoleophobic coating for effective oil-in-water emulsion separation

Herein, hydrophobic PVDF membranes were facilely transformed into highly hydrophilic and underwater superoleophobic ones via one-step dip-coating in tannic acid (TA)/sodium periodate (NaIO4)-mixed solution. The employment of NaIO4 could not only facilitate TA oxidation and deposition, but also introduce abundant hydrophilic carboxyl groups on membrane surface. Consequently, compared with the pristine PVDF membrane, the modified membrane showed much higher hydrophilicity and underwater oleophobicity with water contact angle decreasing from 121° to 32°, oil contact angle increasing from 116° to 162° and a tilt angle of just 2°. In contrast to the two-step modification (deposition of TA followed by post-oxidation by NaIO4), our approach endowed the membrane with dramatically improved permeability (>2400 LMH/bar) and oil rejection (>98%) when dealing with different types of oil-in-water emulsions. Additionally, the membrane displayed excellent antifouling performance with flux recovery ratios of above 95% and favorable reusability after 5-cycle filtration tests. Moreover, the membrane possessed a stable TA coating even being subjected to harsh pH solutions or sonication. This work provides a simple, robust and cost-effective strategy for membrane modification.

A comprehensive description of the threshold flux during oil/water emulsion filtration to identify sustainable flux regimes for tannic acid (TA) dip-coated poly(vinylidene fluoride) (PVDF) membranes

In the separation of oil/water emulsions using membrane separation methods, fouling remains a problem. To improve the fouling resistance effectively, a hydrophilic tannic acid (TA) coating was constructed on the poly(vinylidene fluoride) (PVDF) membrane via dip-coating method. Both the wettability and surface free energy were dramatically enhanced after the introduction of the TA coating. TA deposition with extended dip-coating time did not result in a corresponding increase in the pure water permeate quality, suggesting that there is a trade-off between the enhanced surface hydrophilicity and diminished pore size. Furthermore, the threshold fluxes were determined using the flux-stepping method, and explored to provide guidance on membrane fouling rates for oil/water emulsion filtration. The hydrophilic TA dip-coated PVDF membrane prepared at a dip-coating time of 9 h exhibited the highest threshold flux compared to the other membranes. The experimental evidences of the threshold fluxes can be used to predict the sustainable flux regimes for the TA dip-coated membranes. Constant flux verifiable experiments for oil/water emulsion were performed at fluxes near and below the threshold fluxes. By selecting a constant flux strategy below the threshold flux, membrane over-fouling can be avoided efficiently and the operating period can be prolonged favourably. More generally, operation below the threshold flux recognizes a modest fouling level, arising from the sufficient flux, which would result in the infrequent need for cleaning and is a compromise between capital expenditure and operating costs.

Layer-by-layer deposition of tannic acid and Fe3+ cations is of electrostatic nature but almost ionic strength independent at pH 5

The step-by-step assembly of tannic acid (TA) and of Fe3+ cations allows to produce films of controlled thickness using exclusively small multivalent ions. In the present investigation, it is shown that even if electrostatic interactions are dominant over ligand to metal charge transfer interactions in stabilizing such films, those electrostatic interactions display a small sensitivity to concentration in NaCl used as a supporting electrolyte as well as to the concentration in sodium acetate in the absence of NaCl. This finding highlights the strong stability of the films obtained through the step-by-step deposition of TA and Fe3+ cations. Complementarily, the films made from 6 deposition cycles of TA and Fe3+ cations do not form Prussian Blue when put in contact with hexacyanoferrate anions. This shows that Fe3+ is so tightly bound to the film that it is not able to form a coordination polymer with Fe(CN)64− anions.

PH- and glutathione-responsive release of curcumin from mesoporous silica nanoparticles coated using tannic acid–Fe(iii) complex

A novel pH- and glutathione-responsive drug delivery system has been developed by deposition of tannic acid (TA)–Fe(iii) complex on the surface of mesoporous silica nanoparticles (MSN).

Phenolic film engineering for template-mediated microcapsule preparation

Microcapsules are of scientific and technological interest because of their ability to encapsulate cargo inside their hollow interiors, thereby separating and protecting the cargo from the external environment. Both template-free and -mediated strategies have been exploited to prepare microcapsules. For the latter strategy, coating sacrificial particulate templates with robust films is a key step towards obtaining mechanically-stable hollow architectures following template removal. In this review, we focus on phenolic-based film engineering techniques utilizing dopamine (DA) and tannic acid (TA), which have recently emerged as new platforms for template-mediated capsule preparation. The first part of the review describes the self-polymerization of DA, which preferentially occurs at interfaces. The second part of the review describes TA capsules. Particular emphasis is placed on the coordination-triggered rapid deposition of TA on different substrates. These examples highlight the versatility and simplicity of phenolic film engineering strategies for microcapsule preparation. Phenolics are abundant bio-based materials, and thus form an attractive field of research for the future development of microcapsules. This focus review summarizes advances in the recently emerging field of phenolic film engineering for template-mediated microcapsule preparation. By depositing polyphenol films on sacrificial particulate templates and subsequently removing the templates, hollow microcapsules can be readily prepared. Due to the pH-responsive properties, negligible cytotoxicity and the bioactivities of the phenolic building blocks (dopamine and tannic acid), phenolic microcapsules are promising for biomedical applications.

Nano-engineered Microcapsules of Tannic Acid and Chitosan for Protein Encapsulation

Tannic acid (TA), a high molecular weight polyphenol of natural origin, was assembled in alternation with chitosan (CH) using a layer-by-layer technique. The deposition of tannic acid and chitosan layers on flat supports was monitored by quartz crystal microbalance, UV-vis spectroscopy, and electrophoretic mobility measurements on microparticles. Hollow (TA/CH)4 capsules were built and their permeability as a function of pH and molecular weight of a penetrating compound was investigated. The pH-permeability threshold for TA/CH capsules is shifted to lower pH for 2 pH units, as compared with commonly used polyallylamine/polystyrene sulfonate capsules. A more pronounced dependence of the TA/CH capsules' permeability on molecular weight of encapsulated substances allows better control over their release properties. Bovine serum albumin was loaded into (TA/CH)4 capsules using a pH-driven method and released by decreasing pH. Biocompatible tannic acid/chitosan films and capsules have advantages toward capsules made of synthetic polyelectrolytes for drug encapsulation and as delivery and depot systems. Incorporating a layer of tannic acid with proved antioxidant and antimicrobial properties into capsule walls, provides defense for encapsulated materials.

Tannic acid binding of cell surfaces in normal, premalignant, and malignant squamous epithelium of the human uterine cervix.

Alterations in tannic acid (TA) binding capacity of cell surface carbohydrates in normal, premalignant, and malignant squamous epithelium of the human uterine cervix have been studied using electron microscopic visualization in combination with microdensitometric evaluation. While in normal epithelium there is distinct binding in four to five cell layers of the deep intermediate zone, cells of carcinoma in situ and invasive cancer lesions lack TA binding. In moderate dysplasia an intermediate reacting pattern is found. Deep intermediate cells in areas bordering the carcinoma in situ lesions do not show any binding, although their ultrastructure cannot be distinguished from similar cells in normal tissue. The TA deposition within the deep intermediate zone is probably related to the presence here of glycoprotein-containing membrane-coating granules. The finding that TA binding discriminates between cells in normal squamous epithelium and morphologically normal cells in juxtaposition with lesional areas in premalignant and malignant epithelium opens the possibility for a more reliable cytologic diagnosis of cervical epithelial neoplasia.