Water-based Polymers Research Articles

Stability of Ti3C2-MXene/Waterborne polyurethane composite emulsion and investigation of visible light-driven film self-healing performance

Intrinsic self-healing waterborne polyurethane (WPU) is an environmentally friendly, economically viable, and practical novel intelligent material. However, the key to achieving practical applications lies in the remote activation of repair in self-healing materials and the excellent mechanical properties of the matrix. In this study, we introduce quadruple hydrogen bonding in the polyurethane backbone. We have incorporated a novel two-dimensional sheet-like material, MXene, to achieve visible light remote-driven self-healing of material hydrogen bonds while enhancing the material’s mechanical properties. By utilizing the MXene supernatant, this approach not only resolves the issues of poor stability and easy sedimentation of MXene nanosheets in water-based polymers but also helps to prevent resource wastage. Our research results demonstrate that the composite film exhibits a tensile strength of 6.55 MPa and a fracture elongation of 604%. Additionally, quadruple hydrogen bonds in the WPU chains enable rapid self-healing of microcracks under visible light irradiation at 300 mW/cm2, with complete disappearance within 80 min.

Global Research Trends in Engineered Soil Development through Stabilisation: Scientific Production and Thematic Breakthrough Analysis

Soil, a naturally occurring resource, is increasingly used as a construction material. Stabilisation strengthens soil, which is weak as an engineering material. Stabilising soil changes its physical qualities, enhancing its strength. Soil stabilisation increases the shear strength and load-bearing capacity. Soil stabilisation refers to any endeavour to change natural soil for engineering purposes using physical, chemical, mechanical, or biological methods, or a mix of these. Strengthening road pavements includes improving the load-bearing capacity, tensile strength, and performance of unstable subsoils, sands, and waste materials. Due to market demands and scientific advances, the number of soil-stabilising additives has increased. These innovative stabilisers include reinforcing fibres, calcium chloride, sodium chloride, and cross-linking water-based styrene acrylic polymers, which are geopolymers that boost the load-bearing capacity and tensile strength of soil. Many materials are being explored for soil stabilisation. In this article, the authors investigated the direction of soil stabilisation research. Scientometric analysis identifies stabilisation challenges and research trends in the field. This study analysed research patterns by countries, authors, institutions, keywords, and journals from 1959 to 2023; in 2021, 150 articles were published, which was the highest number in a year. Citations peaked at 3084 in 2022. With 253 publications and 3084 citations, India was the most productive country. Iran and France published the fewest, 34 and 33, respectively. The Islamic Azad University and the National Institute of Technology had the fewest published articles with 17 articles. This work can help track soil stabilisation research and will serve as an information document for future research.

Preparation and Use of Low-Cost Electrochemical Sensors

Since the decade of the 90s when the first works of professor Joseph Wang were published, screen-printed electrodes have been proposed for many objectives. In the first works in Brazil a few years later, some authors proposed electrochemical sensors using graphite from batteries, which provide great results for the determination of several analytes.1 In another interesting work, Professor Lucio Angnes (USP) and collaborators prepared gold electrodes from CD, which presented a thin film of the noble metal.2 They obtained an extremely low-cost electrochemical sensor. After that, this research line gained notoriety in Brazil, and the number of groups and papers has increased considerably. In this regard, we can highlight some researchers that have been working on low-cost and disposable electrochemical sensors, including Lauro Kubota (UNICAMP), Luiz Humberto Marcolino Junior (UFPR), Márcio Fernando Bergamini (UFPR), Ronaldo Censi Faria (UFSCar), Éder Cavalheiro (USP), Osvaldo Novais de Oliveira Junior (USP), Sergio Spínola (USP), Murilo Santiago (CNPEM), Renato Souza Lima (CNPEM), Orlando Fatibello Filho (UFSCar), Wendell Coltro (USP), William Reis (UNICAMP), and Thiago Paixão (USP). The laboratory of Sensors, Nanomedicine, and Nanostructured Materials (LSNano) located at UFSCar Araras has also developed low-cost sensors using recyclable materials and conductive inks with simple preparation. Low-cost electrodes can be prepared with infinite possibilities by using different substrates, such as circuit boards,3 acetate sheets,4 and polyethylene terephthalate (PET) from bottles5 as well as paper6. In the last example, various types of papers have been applied in this area, including cardboard,7 waterproof,6 and adhesives8. Therefore, materials that we use daily can become important devices with great applications. There are many options to produce low-cost electrochemical sensors, including pencil drawing, stencil, laser scribing, and screen-printing techniques.9 The strategy depends on the subject and the materials that have been deposited to be used as conductors. In this context, the screen-printing technique is come from the t-shirt preparation and is an excellent alternative to produce hundreds of sensors in a few minutes. They can be applied by using different electrochemical techniques, such as potentiometry, voltammetry, and electrochemical impedance spectroscopy. For this purpose, low-cost inks, which are made of a polymer and a conductive material, are necessary. Conductive inks can be prepared with water based-polymers,10 nail polish,11 and traditional polymers based on organic solvents12. Otherwise, graphite carbon nanotubes and/or graphene and carbon dots have been used as conductive carbon-based materials.13 Also, metallic nanoparticles such as copper, platinum, and gold can be great alternatives for this intention but can be quite costly.

Intrinsic permeabilities of transparent soil under various aqueous environmental conditions

This study investigates the intrinsic permeability of two water-based transparent soil surrogates (Aquabeads and hydrogel beads) in various aqueous environments. To maximise the efficiency of seepage tests for different solutes (salt and a surfactant) at different concentrations, a rapid approach was established to estimate the intrinsic permeabilities of these water-based granular polymers. Due to the geometric similarity of the pore structures formed by the packing of granular polymer beads of different sizes, the Kozeny–Carman permeability estimation can be directly applied to study the permeability (K), which primarily varies with the effective diameter (de). A systematic sieving analysis of these polymers was conducted to determine the values of both deand K. The experimental results showed that both parameters monotonically decrease with increasing solute concentration. The critical shrinkage concentrations for salt and the surfactant were identified as 5–7 ppt and 0·02% (mass/volume), respectively. This study represents the first contribution to providing a sound understanding of the intrinsic permeabilities of these surrogate soils when saturated with various solutions. This study contributes to the physical modelling in geotechnics when using those materials.

Effect of water-based polymers of cement base with fly ash on the stress and strain of concrete in the metro segment

This Research Aimed To Examine The Effect Of Water-Based Polymers Of Cement Base With Fly Ash On The Displacement Of Concrete In The Urban Metro Segment. The Mix Variants Of The Study Are Comprised Of 2 Water/Cement Ratios Of 0.5 And 0.45, Each Of Which Has Four Weight Ratios (5%, 10%, 15%, 20%) Of Fly Ash Added To The Cement, Amassing Eight Different Mixes. Moreover, 150x150x150 Mm Cubic Molds Were Used For Sample Preparation And Sampling. Nine Cubic Samples Were Retrieved From Each Mixing Scheme. After Removing The Samples From The Mold, They Were Compressed For 7, 28 And 42 Days. The Findings Indicated That The Concrete Samples Of The Variant With The Water/Cement Ratio Of 0.45 And Fly Ash/Cement Ratio Of 15% Exhibited Maximum Strength. The Maximum Displacement Values ​​Before The Earthquake Were 12.4 Cm In The Vertical Direction For Concrete With Fly Ash And 18.4 Cm For The Applied Concrete. After The Earthquake, These Values ​​Were 25.4 Cm And 36.4 Cm, Respectively. Also, The Displacement Values In The X Direction Have Decreased By 5 To 6 Cm At Different Loading Steps.

Adhesive Performance of Acrylic Pressure-Sensitive Adhesives from Different Preparation Processes.

A series of pressure-sensitive adhesives (PSAs) was prepared using a constant monomeric composition and different preparation processes to investigate the best combination to obtain the best balance between peel resistance, tack, and shear resistance. The monomeric composition was a 1:1 combination of two different water-based acrylic polymers—one with a high shear resistance (A) and the other with a high peel resistance and tack (B). Two different strategies were applied to prepare the adhesives: physical blending of polymers A and B and in situ emulsion polymerization of A + B, either in one or two steps; in this last case, by polymerizing A or B first. To characterize the polymer, the average particle size and viscosity were analyzed. The glass transition temperature (Tg) was determined by differential scanning calorimetry (DSC). The tetrahydrofuran (THF) insoluble polymer fraction was used to calculate the gel content, and the soluble part was used to determine the average sol molecular weight by means of gel permeation chromatography (GPC). The adhesive performance was assessed by measuring tack as well as peel and shear resistance. The mechanical properties were obtained by calculating the shear modulus and determination of maximum stress and the deformation energy. Moreover, an adhesive performance index (API) was designed to determine which samples are closest to the requirements demanded by the self-adhesive label market.

Fluorocarbon Rubber-Based Inert Dry Adhesive for Applications under Harsh Conditions

Artificial dry adhesives have been developed based on materials and production methods by many researchers. Nowadays, extensive research has attempted to apply dry adhesives to various industrial fields, such as glass transportation systems, with admirable performance. However, most artificial dry adhesives consist of polymers such as thermosetting polymers, ultraviolet curable polymers, and water-based polymers. These polymers exhibit low thermal resistance and outgassing under high-vacuum conditions. Hence, the usage of dry adhesives under high-temperature and vacuum conditions, such as semiconductor manufacturing processes, is critically limited. In this study, based on the contact mechanism, a dry adhesive for use under high-temperature and vacuum conditions is developed using fluorocarbon rubber with excellent thermal resistance and low outgassing properties. The fluorocarbon rubber dry adhesive (FDA) material shows a high pull-off strength of up to 24.1 N cm–2 and its performance is verified through various experiments. Glass transportation experiments using a robot arm and custom-built equipment are also conducted and the results confirm the feasibility of using FDA in industrial applications. The FDA is expected to be a useful alternative under high-temperature and vacuum conditions, such as those in the aerospace industry and display manufacturing processes.

A waterborne polyurethane–based leather finishing agent with excellent room temperature self-healing properties and wear-resistance

Water-based polymers have been widely used in coating materials, but their durability and service life are often greatly reduced due to macroscopic damage or cracking caused by external forces. In this paper, poly(propylene glycol) terminated with ortho-amiomethylphenyl diboronic acid (AMPBA-PPG) and cross-linked polymer containing boroxine (CLP-boroxine) were synthesized by nucleophilic substitution. Then the CLP-boroxine was introduced into waterborne polyurethane (WPU) to prepare AMPBA-PPG/WPU composite emulsion for leather finishing and CLP-boroxine/WPU composite film. The self-healing characterization results showed that the self-healing efficiency of the 15 wt% CLP-boroxine/WPU film was as high as 93.6% after only 4 h of water stimulation at room temperature. Compared with neat WPU finished leather, the leather samples finished with AMPBA-PPG/WPU exhibited more excellent wear-resistance. More importantly, the leather coating finished with AMPBA-PPG/WPU still showed nice wear-resistance even after wear and self-healing treatment. These results are attributed to that the hydrogen bonds between AMPBA-PPG and WPU, WPU, and WPU, and the dynamic reversible covalent bonds in AMPBA-PPG can improve/increase the self-healing efficiency of the composite coating. In addition, the boron hydroxyl groups in AMPBA-PPG could also react with the hydroxyl groups on the leather surface, thereby further improving the wear-resistance of the leather coating. Dynamic boronate ester bonds can not only endow WPU excellent self-healing properties but also improve wear-resistance of its leather coating.

Nanocellulose in Emulsions and Heterogeneous Water-Based Polymer Systems: A Review.

Nanocelluloses (i.e., bacterial nanocellulose, cellulose nanocrystals, and cellulose nanofibrils) are cellulose-based materials with at least one dimension in the nanoscale. These materials have unique and useful properties and have been shown to assemble at oil-water interfaces and impart new functionality to emulsion and latex systems. Herein, the use of nanocellulose in both emulsions and heterogeneous water-based polymers is reviewed, including dispersion, suspension, and emulsion polymerization. Comprehensive tables describe past work employing nanocellulose as stabilizers or additives and the properties that can be tailored through the use of nanocellulose are highlighted. Even at low loadings, nanocellulose offers an unprecedented level of control as a property modifier for a range of emulsion and polymer applications, influencing, for example, emulsion type, stability, and stimuli-responsive behavior. Nanocellulose can tune polymer particle properties such as size, surface charge, and morphology, or be used to produce capsules and polymer nanocomposites with enhanced mechanical, thermal, and adhesive properties. The role of nanocellulose is discussed, and a perspective for future direction is presented.

Enhancing H2-permselectivity of high-flux hollow fiber membrane via in-situ layer-by-layer surface treatment

This manuscript presents the first application of a layer-by-layer (LbL) permselective all-polymer coating to a Torlon© polyamide imide (PAI) hollow fiber substrate to realize a new class of manufacturable, highly selective, composite polymer membrane for hydrogen separation from carbon dioxide and nitrogen light gases. Sub-micron, defect-free conformal coatings of [PEI10/PAA4] polymeric pair were successfully deposited on both PEI-functionalized and untreated hollow fiber substrates. Surface functionalization was found to provide twofold benefits of introducing a positively charged surface to aid LbL deposition while enhancing selective transport of hydrogen through the membrane achieving high selectivities of H2:CO2 (>200:1) and H2:N2 (>2000:1) at 40 Barrers of H2 permeability exceeding the Robeson upper bound for homogenous polymer films. The deposition of low-cost, water-based polymers and easy to fabricate LbL membranes on conventional hollow fiber has potential use at industrial scale for hydrogen separation.

Study on a novel poly (vinyl alcohol)/graphene oxide-citicoline sodium-lanthanum wound dressing: Biocompatibility, bioactivity, antimicrobial activity, and wound healing effect

Although graphene oxide (GO) is widely used as an antibacterial agent, its efficacy still needs to be improved. In this work, we present a novel medical dressing that improves antibacterial effect and promotes wound healing. Poly (vinyl alcohol)/graphene oxide-citicoline sodium-lanthanum (PVA/GO-CDPC-La) films were prepared by the solution intercalation method for usage in wound dressing applications. GO was modified by zwitterionic citicoline (CDPC) to improve the dispersibility of water-based polymers, while providing La3+ ions with more adsorption sites and enhancing the antibacterial properties of the film. Water absorption experiments showed that it could effectively absorb wound exudate while keeping the wound moist. In vitro cytotoxicity and cell adhesion experiments showed that the PVA/GO-CDPC-La films acknowlhad good biocompatible and promoted wound healing. Bacterial adhesion experiments showed PVA/GO-CDPC-La could greatly reduce the risk of wound infection. Furthermore, in vivo wound healing experiments showed that wounds treated with the film healed faster postoperatively and histological observations showed that a mature epidermal architecture was formed, which could be used as a wound-dressing material.

Synthomer to buy Omnova

The British specialty polymer maker Synthomer has agreed to acquire US-based Omnova Solutions for about $824 million. Synthomer says the purchase will create a global specialty chemical company with a broad range of polymer chemistries. Synthomer, formerly called Yule Catto, had sales last year of about $2 billion, mainly of aqueous dispersions, specialty additives, and elastomers such as nitrile butadiene rubber. Omnova’s sales were $770 million and included surface treatments, styrene-butadiene paper coatings, and coated fabrics such as wallpaper. Together, according to a Synthomer presentation for analysts, the two firms will create a major player in water-based polymers with strong raw material integration. Synthomer anticipates about $30 million in annual cost savings from delisting Omnova from the stock market and various office and business consolidations. The transaction is a victory for Anne P. Noonan, who joined Omnova in 2014 and became its CEO in late 2016. The firm had been

Hybrid graphene oxide decoration and water-based polymers for mild steel surface protection in saline environment

Nitrogen, sulfur and phosphorous atoms were chemically introduced to graphene oxide nanostructure (NSP-GO) to construct a corrosion inhibitor for mild steel in a 3.5 wt% NaCl solution. The anticorrosive effects of NSP-GO on two synthesized water-soluble polymeric compounds, melamine formaldehyde (MF) and urea formaldehyde (UF), were investigated in the saline environment. With NSP-GO, the inhibition efficiency of 93% (for UF) and 95% (MF) reached to ˜100% for both composites at 500 ppm concentration. The heteroatoms of decorated GO sheets act like anchors to pull GO sheets towards the metal surface and make MF and UF polymers films as full protectors.

Preparation of disperse inks for direct inkjet printing of non-pretreated polyester fabrics.

The preparation of disperse inks for direct inkjet printing was carried out using disperse dye, dispersant (TD-1109, hydrophilic polyacrylic acid block copolymer), wetting agent (diethylene glycol and ethylene glycol), water-based polymers (polyvinyl alcohol (PVA) or waterborne polyester), deionized water, etc. The suitability of disperse inks for polyester fabrics was assessed via measurement of conductivity, pH, particle size surface tension and viscosity. The theological behavior of disperse inks was evaluated by rotational viscometry; the disperse inks had the characteristics of a Newtonian fluid. The inkjet printability of disperse inks was investigated by monitoring droplet formation dynamics, where the viscosity and surface tension of disperse ink were 2.78 mPa s and 33.28 mN m−1, respectively. The disperse ink has excellent ejection performance. The printing accuracy of disperse inks was evaluated by inkjet printing quality of lines on untreated polyester fabrics. The fastness properties of printed polyester fabrics were also evaluated and they presented excellent color fastness. Compared with different printed polyester fabrics, the polyester fabrics printed with disperse ink made from water-based polymers have high color strength (K/S) and saturation (C*) values.

An oil-based gel system for reservoir rock permeability modification

Water production during gas and oil recovery is a major problem for the oil industry, as the average worldwide production is more than five barrels of water per barrel of oil. Among the many attempted remedies, water-based polymers and cross-linked gels are often injected into the reservoir to control excessive water production. Recently, oil-based gelant systems have been proposed which are oil-soluble. These systems react with the reservoir water to form a rigid water-based gel during the shut-in period, thereby drastically reducing the permeability of the reservoir to water. The aim of this paper is to improve the understanding of how the flow of oil and water are affected by one of the oil-based gelant systems, TMOS. The gelation behaviour and gel characteristics were studied under static and dynamic conditions. Two-dimensional transparent glass models were used to study the effect of gelant flow, and evaluate the effectiveness of the gel in modifying the oil and water permeability. The ability of the gel to modify the water flow at different flow velocities yields a velocity-dependent permeability. New insights are presented that may help reservoir and production engineers to select and design better gel treatments for a given reservoir.

The Application of a Water-Based Hybrid Polymer Binder to a High-Voltage and High-Capacity Li-Rich Solid-Solution Cathode and Its Performance in Li-Ion Batteries

Recently, water-soluble and aqueous polymers (water-based polymers) have attracted much attention as binders for lithium ion batteries (LIBs) because of the need for low-cost materials and environmentally compatible electrode fabrication processes. For example, N-methyl-2-pyrrolidone (NMP), which is listed as a carcinogenic chemical with reproductive toxicity is often used as a solvent to prepare a slurry (cathode material particle/conducting carbon additive/conventional polyvinylidene difluoride (PVdF) binder/ NMP solvent) employed in the fabrication process of electrode films on current collectors; this slurry should be recycled without releasing it to the atmospheric environment. Therefore, switching from a nonaqueous-based fabrication process to an aqueous-based process has been widely investigated. The hurdles in developing water-soluble and aqueous polymer binders for use in cathodes in LIBs are still high; improvements are necessary to increase the resistance to electrochemical oxidation and dissolution of metal oxide surfaces in water. In order to overcome these problems, a variety of polymer materials have been applied in the fabrication of cathodes with water-based slurries. In recent years, Li-rich solid-solution layered cathode materials comprising layered LiMO2 (M: transition metals) and Li2MnO3 have attracted much interest because some materials exhibit capacities as high as 250 mAh g-1 in the voltage range of 2.0 and 4.8 V. These materials are charged to above 4.5 V (vs. Li/Li+) to fully activate the Li2MnO3 component, and after activation, the cathodes are charged to 4.5 V to reach discharge capacities over 250 mAh g-1. To use these promising high-voltage and high-capacity cathodes in the next-generation Li-ion batteries prepared in environmentally compatible electrode fabrication processes with a water-based binder, water-based binders having high resistances to electrochemical oxidation during charging process should be developed. In this study, an aqueous hybrid polymer (TRD202A, JSR), which was composed of acrylic polymer and fluoropolymer, was selected as a binder for the Li-rich solid-solution layered cathode material Li[Ni0.18Li0.20Co0.03Mn0.58]O2. A cathode prepared with Li[Ni0.18Li0.20Co0.03Mn0.58]O2 particles, TRD202A binder, CMC and conductive carbon additive was tested and analyzed for charge/discharge capacity, cycle stability, rate performance, mechanical resistance, resistance of electrochemical oxidation, and changes of the surface composition and structure after water-treatment used for preparing water-based slurry. The water-based TRD202A cathode binder is a water-based emulsion and is designed with a unique hybrid polymer developed from acrylic polymer and fluoropolymer to satisfy both the requirements of high adhesion and chemical and electrochemical resistances. Wu and co-workers have already reported an application of the TRD202 binder in a Li-rich solid-solution cathode. They mentioned that the TRD202A binder can be used for high-voltage cathodes in the voltage range of 2.0-4.6 V [1], and its thermal stability is equivalent to that of PVdF. However, they have not examined the water-based binders for charge/discharge capacities, long cycle stability, rate performance, mechanical resistance, resistance of electrochemical oxidation, or changes of the surface composition and structure after water-treatment used for preparing the water-based slurry. We have examined in depth the above points with the Li-rich solid-solution cathode (3/5)Li2MnO3·(1/5)Li[Ni0.5Mn0.5]O2 ·(1/5)Li[Ni1/3Co1/3Mn1/3]O2. [1] Wu Q, Ha S, Prakash J, Dees DW, Lu W (2013) Electrochim. Acta 114:1-6

Highly efficient drug delivery systems based on functional supramolecular polymers: In vitro evaluation

The novel concept of modifying and enhancing the properties of existing functional micelles through self-complementary interactions has significant potential. In this study, a practical approach to living polymerization of functionalized thermoresponsive monomers enabled the incorporation of self-constituted multiple hydrogen bonded groups into micelles that have potential as supramolecular drug-delivery systems. Phase transitions and morphological studies in aqueous solution showed that the microstructure can be controlled to achieve well-defined vesicle-like micelles with respect to the strength of the hydrogen bond segment. Thus, the resulting micelles have a very low critical micellization concentration and very high loading capacity (16.1%), making the loading process extremely stable and efficient. Incorporation of the anticancer drug doxorubicin (DOX) affected the micellization process in aqueous solution and enabled fine-tuning of drug loading and precise control of drug release rate with excellent sensitivity. Release studies in vitro showed that DOX-loaded micelles exerted dose-dependent cytotoxicity against human liver carcinoma (HepG2) cells at the physiological temperature of 37°C. In addition, DOX-loaded micelles were efficiently endocytosed by the cancer cells, which may enable the micelles to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. This newly developed material may provide a potential route towards next-generation drug delivery vehicles. Statement of SignificanceA breakthrough innovation in water-based thermo-responsive polymers has enabled significant progress in developing smart stimuli-responsive nanocarriers by generating novel “supramolecular polymeric micelles” via self-complementary hydrogen-bonding interactions. These newly developed micelles exhibit extremely high micellar stability and drug loading capacity (up to 16%), excellent thermo-responsive behavior and precise control of drug release rate due to hydrogen-bond-induced physical cross-linking. In addition, doxorubicin-loaded micelles were efficiently endocytosed by the cancer cells, which allows them to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. Thus, this work provides a potential route for the development of next generation multifunctional nanocarriers that have improved safety and to increase the therapeutic efficacy of anticancer therapy.

Water-Based Robotic Fabrication: Large-Scale Additive Manufacturing of Functionally Graded Hydrogel Composites via Multichamber Extrusion

Additive manufacturing (AM) of regenerated biomaterials is in its infancy despite the urgent need for alternatives to fuel-based products and in spite of the exceptional mechanical properties, availability, and biodegradability associated with water-based natural polymers. This study presents water-based robotic fabrication as a design approach and enabling technology for AM of biodegradable hydrogel composites. Our research focuses on the combination of expanding the dimensions of the fabrication envelope, developing structural materials for additive deposition, incorporating material-property gradients, and manufacturing architectural-scale biodegradable systems. This work presents a robotically controlled AM system to produce biodegradable-composite objects combining natural hydrogels, such as chitosan and sodium alginate, with other organic aggregates. It demonstrates the approach by designing, building, and evaluating the mechanics and controls of a multichamber extrusion system. Finally, it provides evidence of large-scale composite objects fabricated by our technology that display graded properties and feature sizes ranging from micro- to macroscale. Fabricated objects may be chemically stabilized or dissolved in water and recycled within minutes. Applications include the fabrication of fully recyclable products or temporary architectural components such as tent structures with graded mechanical and optical properties. Proposed applications demonstrate environmental capabilities such as water-storing structures, hydration-induced shape forming, and product disintegration over time.

Nanotubular Hydrogen-Bonded Organic Framework Architecture of 1,2-Phenylenediboronic Acid Hosting Ice Clusters

A nanotubular crystal network of a small-molecule compound, 1,2-phenylenediboronic acid, constituting a hydrogen-bonded organic framework (HOF) architecture is presented. In contrast to the carbon nanotubes, the intermolecular connections are based strictly on hydrogen-bonding interactions. Its uniqueness is additionally enhanced by the existence of the other two crystal phases characterized by more compact structures. Furthermore, the experiment and computational analysis show that such channels may host water clusters, such as water-based polymers similar to the ones found in the hexagonal structures of ice. Water molecules incorporated into pores interact weakly with the boronic framework and, thus, are not responsible for the framework templation.

Correlation between water permeability of latex-modified concrete (LMC) and water diffusion coefficient of latex film

Cement-based materials are generally known as weak materials in flexure and tension in comparison with compression. Polymers are used in cement-based materials to improve their flexural and tensile behaviors. The composite is called as polymer-modified concrete/mortar. Furthermore, polymers decrease permeability of water into cementitious matrices. Polymers are usually used as admixtures in concretes in form of latexes. Latexes are water-based polymers, which are consistent with water-based concrete matrices. On this basis, these kinds of products are called latex-modified concretes (LMCs). However, it has been found that chemical composition, particle size distribution, molecular weight, physical/mechanical properties of latexes affect performance of modified concretes. In this investigation, six latexes in three categories (acrylic, SBR and polyvinyl acetate) were used as concrete admixtures. They were characterized for chemical composition (by FTIR analysis), minimum film formation temperature, pH, glass transition temperature (T g), particle size and particle size distribution to evaluate the effect of each property on LMC performance. Due to the formation of latex film in the microcracks and pores of concrete microstructure, it was suggested that diffusion of water into films controls permeability of whole concrete structures. On this basis, the diffusion coefficient of the latex films subjected to water was measured using a new method (continuous FTIR analysis). Capillary water absorption test was performed on concrete specimens to verify validity of the suggestion. It was found that there is a correlation between capillary water absorption of LMCs and water diffusion coefficient of latex films.