Intermolecular Interaction Forces Research Articles

Computation of Binding Energy of MCS and GO-Grafted MCS with Waterborne Epoxy Resin Using Density Functional Theory Method: Investigating the Corrosion Resistance of the Composite Coatings.

In order to overcome the problems of poor corrosion resistance and low hydrophobicity of water-based coatings. Two corrosion-inhibiting materials, graphene oxide (GO) and modified chitosan (MCS), were added to the coatings to obtain a new type of coating with comprehensive properties. The composite material formed by PVA cross-linked waterborne epoxy resin was named "substrate". The density functional theory (DFT) calculation was used to explore the binding ability of MCS and GO-grafted MCS to the substrate, respectively. The results showed that the complex cross-linked network structure formed by the grafting of GO and MCS not only improved the intermolecular interaction force but also improved the binding ability to the substrate, and the coating is denser, effectively delaying the erosion to the coating by the corrosive medium. The composite coating exhibited excellent dual functional properties of hydrophobicity and corrosion resistance at the coating-metal interface, and a stronger protective effect was formed upon the steel plate. Studies showed that this composite coating has good hydrophobic properties. (The contact angle of the composite waterborne coating reaches 87°.) It also has low self-corrosion current (0.28/cm-2) and high corrosion voltage (-0.45 V). The maximum inhibition efficiency of the coating is 99.97%.

Methane absorption of coal-measure shales with and without pore water from the Qinshui Basin, North China: Based on high-pressure methane absorption experiments

The coal-measure shale in the Qinshui Basin, North China has a high thermal maturity and a huge shale gas resource, but studies related to its gas-bearing property (GBP) are lack. In this paper, shale samples taken from the carboniferous coal-measure strata in the Yangquan block of Qinshui Basin were mainly investigated on their pore water contents and occurrence characteristics, and their high-pressure methane adsorption capacities under the dry and moist conditions. The results show that the pore water in the shale is in an ultra-low saturation state, occurring mainly in clay minerals (91% on average), significantly decreases its effective pore structure parameters, especially the nonmicropore specific surface areas (by 70.21% on average), and reduces its methane adsorption capacity (by 33% on average at 30 °C), with the adsorbed methane occurring mainly in micropores and controlled by the TOC content. The adsorption of methane on the shale is an exothermic process, and both the shale adsorption capacity and adsorbed methane density are reduced with increasing temperature. Pore water not only has a competitive adsorption with methane, but also weakens the adsorbed methane inter-molecular interaction forces, decreasing the methane adsorption capacity, especially under the low temperature and pressure conditions. The GBP models of a selected shale under the dry and moist conditions further indicate that pore water also decreases the adsorbed gas percentage to some extent, especially at a burial depth < 1500 m, and the adsorbed gas is dominant in the shale. These GBP characteristics of coal-measure shale should pay a great attention in the future exploration and development of shale gas in the Qinshui Basin.

Insights into ultrasound-induced starch-lipid complexes to understand physicochemical and nutritional interventions

Novel lotus root starch (LRS)-myristic acid (MA) complexes were prepared using an ultrasound-assisted hydrothermal method (UHM) to investigate its nutritional intervention in type 2 diabetes mellitus (T2DM). Ultrasonic treatment promoted the formation of the V-type crystal structure of the complex and improved the intermolecular interaction force, the order of the short-range starch molecules, and crystallinity. The volume of the ultrasound-assisted LRS-MA composite (U-LRS-MA) particles was enlarged, the particle distribution showed non-uniformity, and the surface grooves were deepened. The resistant starch content of U-LRS-MA was greatly increased from 34.58 % of native starch to 68.20 %. Dietary Supplements of 5 % and 15 % U-LRS-MA significantly reduced the body weight, the organ index and fasting blood glucose of T2DM mice, effectively adjusted its blood lipid level, alleviated its liver damage and increased the levels of colonic short-chain fatty acids. The addition of 5 % U-LRS-MA was more effective in T2DM than 15 % U-LRS-MA. Ultrasound could be effectively employed to prepare lipid-starch complexes, namely type 5 resistant starch, which was proved for the first time to have an excellent intervention effect on T2DM.

Geoenvironmental aspects of mine methane emissions

&#x0D; &#x0D; &#x0D; The purpose of the work is to reveal the regularities of the influence of the gaseous phase on the process of filtering carbonated liquid and to characterize the physi-cochemical processes during the implementation of the method of reducing mine methane emissions. The development of minerals can be accompanied by the release of a large amount of methane into the mined-out space. This leads to atmospheric air pollution and consequently to ecological disturbances. This causes methane emissions to the mined-out space and to the surface of the earth cause by the filtration processes of gases and liquids in the rocks. The intensity of fluid filtration through crack and pore systems depends on the content and properties of the fluids and the reservoir properties of the rocks. It is known that methane release to the atmosphere can be observed after mines have been mothballed. This is a problem for many countries around the world where coal and oil and gas fields are being exploited. Investment in methane production and utilization projects is therefore important. Research on fluids filtration processes allow for the development of effective methane recovery methods, and ways to reduce methane emission speed. The result is the reduced air pollution and an improved environmental situation. The paper presents the filtration properties of rocks with different structures and textures. Filtration of carbonated liquid (water-methane) in fractures and pores is considered. It found that an increase in methane concentration in the carbonated liquid leads to a decrease in the phase permeability coefficient for water and an increase for methane. This character of change in phase permeability leads to methane accumulation in crack and pores. The dependence of the average carbonated liquid filtration rate in a rectilinear fracture on the methane concentration and the fracture axis angle of inclination is obtained. The average ascending filtration speed of the carbonated liquid is determined to be greater than the average descending filtration speed. This is due to the effect of the ejection force that acts on the gas bubbles in the liquid. The authors propose a method of blocking methane seepage by physicochemical treatment of the rock mass. The methane blocking effect is achieved by creating a gas-tight zone in areas with a high risk of methane migration to the ground surface. The result is a reduction in methane emissions to the mined-out space and the environment. When the method is realized, the solid product of the polymer solution enters cracks with a disclosure greater than 6 μm or pore channels with an average diameter of 6 μm. At the same time, the water released by the destabi- lization of the polymer solution blocks the methane in small cracks and pores. In pore channels with an average diameter of less than 25 μm, there is a sharp increase in the dynamic viscosity of the polymer solution. This effect is due to an increase in the intermolecular interaction forces between the polymer solution and the walls of the filtration channels. Coagulation and destabilization of the polymer solution in cracks and pores is due to the separation of large agglomerates of macromolecules.&#x0D; &#x0D; &#x0D;

Recent Advances in Mechanical Reinforcement of Zwitterionic Hydrogels.

As a nonspecific protein adsorption material, a strong hydration layer provides zwitterionic hydrogels with excellent application potential while weakening the interaction between zwitterionic units, leading to poor mechanical properties. The unique anti-polyelectrolyte effect in ionic solution further restricts the application value due to the worsening mechanical strength. To overcome the limitations of zwitterionic hydrogels that can only be used in scenarios that do not require mechanical properties, several methods for strengthening mechanical properties based on enhancing intermolecular interaction forces and polymer network structure design have been extensively studied. Here, we review the works on preparing tough zwitterionic hydrogel. Based on the spatial and molecular structure design, tough zwitterionic hydrogels have been considered as an important candidate for advanced biomedical and soft ionotronic devices.

Studies on two phenoxo-bridged homopolynuclear Cu(II) bis(salamo) type complexes based on theoretical calculations and fluorescence properties

The dinuclear Cu(II) complex [Cu2(HL)Br2(MeOH)]·MeOH (1) and the tetranuclear Cu(II) complex [Cu4(L)2](ClO4)2·2EtOH (2), based on a new bis(salamo) type ligand H3L, have been successfully self-assembled and structurally characterized by X-ray single crystal diffraction experiments. In complex 1, the partially deprotonated ligand unit (HL)2– is coordinated with the Cu(II) ions. It is noteworthy that two bromine ions and one methanol molecule with balanced charges are involved in the coordination. Both central coordination Cu(II) ions are five-coordinated. Finally, complex 1 can form a two-dimensional planar network structure and a one-dimensional chain-like structure through intermolecular hydrogen bonds and CH π interactions, respectively. Meanwhile, complex 2 has a centrosymmetric structure with two phenolic oxygen atoms bridging two molecules of metallized ligand [Cu2(L)] units, where Cu1 is five-coordinated and Cu2 is four-coordinated. Thus, complex 2 forms a three-dimensional superamolecular network structure and a one-dimensional chain-like structure through intermolecular hydrogen bonds and π–π stacking interactions, respectively. The energy gaps between the HOMO and LUMO orbitals of complexes 1 and 2 were investigated by DFT calculations, indicating that the complexes are stable. The interaction sites of the ligand with the Cu2+ ions were examined by ESP investigation, and the results are consistent with the crystal structure. The weak intermolecular interaction forces of complexes 1 and 2 were explored by Hirshfeld surfaces and IRI analyses. The luminescent properties of complexes 1 and 2 were illustrated by fluorescence spectroscopy research.

An investigation of a relatively rigid acyclic salamo-type ligand and its square planar Cu(II) complex

A relatively rigid acyclic salamo-type ligand H2L and its square planar Cu(II) complex, [Cu(L)]·CH3OH, were synthesized and characterized by X-ray crystallography, as well as Fourier-transform infrared spectra, UV–Vis spectra, Hirshfeld surface analyses and DFT calculations. The ligand crystallizes in monoclinic space group P 21/c and has pairs of intramolecular hydrogen bonds between the oxime nitrogen atoms and the hydroxyl groups. The Cu(II) complex crystallizes in the monoclinic space group P 21/c. The Cu(II) ion is located in the N2O2 cavity of the fully deprotonated salamo-type ligand (L)2− unit, thus forming a four-coordinate distorted square planar geometry. At the same time, a belt-like, 2-D supramolecular structure is formed by the interaction of intermolecular hydrogen bonds, and the intermolecular interaction force is quantitatively analyzed by Hirshfeld surfaces. Significantly, fluorescence properties of the ligand and its Cu(II) complex were also studied. The coordination ratio of the Cu(II) complex was proved by UV–Vis and fluorescence titration experiments.

Toxicity of dibutyl phthalate to pakchoi (Brassica campestris L.): Evaluation through different levels of biological organization

Dibutyl phthalate (DBP) is a typical persistent organic pollutant with a high load in the agricultural soils of vegetable crops. Currently, studies on the toxicity of DBP in vegetable crops are limited. Therefore, in this study, pakchoi (Brassica campestris L.), a typical vegetable crop, was used to evaluate the toxic effects of DBP. Pakchoi was exposed to DBP for 24 d at three doses (2, 20, and 200 mg/kg), and the phenotypic, biochemical, and molecular indicators were determined. The results revealed that DBP could reduce the emergence of pakchoi and inhibit plant height, root length, fresh weight, and leaf area. At the biochemical level, DBP exposure could reduce the content of three typical photosynthetic pigments (chlorophyll a and b and carotenoids). The effects of DBP exposure on the quality of pakchoi were primarily through reduced soluble sugar and increased proline contents. In addition, O2·− and H2O2 levels increased after DBP stress, and the corresponding antioxidant enzymes (SOD, POD, and CAT) were activated to resist oxidative damage. The dose- and time-dependent toxicities of DBP to pakchoi were demonstrated using an integrated biological response index. Finally, the molecular-level results on Day 24 showed that the three antioxidant enzyme genes (sod, pod, and cat) were significantly downregulated, and the antioxidant enzyme genes were more sensitive biomarkers than the enzyme activities. However, the expression level of enzyme genes was opposite to that of enzyme activity (SOD and POD); thus, DBP might directly interact with these enzymes. Molecular docking showed that DBP could stably bind near the SOD/POD active center through intermolecular interaction forces. This study provides essential information on the risk of DBP toxicity to vegetable crops.

Identification of novel umami peptides from Boletus edulis and its mechanism via sensory analysis and molecular simulation approaches

The study aimed to identify umami peptides from Boletus edulis and explore their umami mechanism. 421, 713 and 616 peptides identified by LC-MS/MS from control sample (CS), enzymatically extracted sample (EES) and high-pressure cooking sample (HPCS), respectively. According to molecular docking study, three potential umami peptides (DGF, KCGQ and HHYE) were chemically synthesized for sensory evaluation. DGF/HHYE had the lowest umami recognition threshold values in the absence (0.37 mmol/L for DGF)/presence (0.21 mmol/L for HHYE) of monosodium l-glutamate. KCGQ exhibited the strongest synergistic umami effect. Molecular dynamic simulation revealed that hydrogen bonds and hydrophobic interactions were the major intermolecular interaction forces and the charged amino acid residues (D1, E4 and K1) in umami peptides were dominate in the molecular recognition of umami peptides and the receptor. This study lays the groundwork for the efficient screening of umami peptides from edible fungi and contributes to the umami peptides structure–activity relationship research.

An elastic organic single crystal with bending and high pressure-induced fluorochromism properties

The mechanically tunable flexible fluorochromic elastic organic single crystals are extremely rare. Fortunately, we prepared a needle-like elastic crystal (TPABA) with bending and high pressure-induced fluorochromism properties. With the reversible change of hydrostatic pressure, the crystal fluorescence underwent reversible red-shift and blue-shift (wavelength change greater than 100 nm). Interestingly, upon bending, the inner and outer arcs on the (002) and (200) surfaces of the crystal exhibited distinct fluorochromic effects by spatially resolved μ-PL measurements. Upon bending, the fluorescence emission of the inner and outer arcs on the (002) face of the crystal was red-shifted and blue-shifted by 26 nm and 4 nm, respectively. Different from (002) face, the inner arc and outer arc of the crystal (200) plane were only blue-shifted and red-shifted by 2 nm and 3 nm, respectively. Theoretical calculations indicated that, on the one hand, with the reversible bending of the crystal, the intermolecular interaction force distance in the crystal would change reversibly, and the corresponding inner and outer arc fluorescence emission wavelengths of the crystal plane would reversibly change. On the other hand, the number of π-π interactions on each face of the crystal had an important effect on the bending-induced fluorochromism of the crystal. This paper provided new idea for the preparation of the multi-faceted bending fluorochromism flexible crystals.

Testing the free particle model: the statistical aspect

In this paper, we analyze the free particle model from the statistical point of view. For this purpose, we consider several examples involving the necessity to take into account the intermolecular interaction or external force fields. It can help students better grasp such an important concept as the free particle and be able to distinguish between its dynamic and statistical contexts.

Synthesis and application of thienylene-vinylene-thienylene derivatives for organic field effect transistors and ammonia sensors

To explore the influence of intermolecular interaction force on the performance of the sensor, a serial of organic semiconductor materials based on thienylene-vinylene-thienylene (TVT) derivatives were synthesized and characterized. X-Ray diffraction measurement of the single crystals of these TVT derivatives show relatively loose herringbone packing structure. Thin film transistors (TFT) based on the TVT derivatives were constructed and showed highest mobility up to 0.69 cm2V−1s−1 for TVT-NA. These OFET decives were further used as gas sensor and the TVT-BF demonstrates good sensitivity and selectivity for detection of ammonia (NH3) gas. The differences in sensing performance is consistent with the simulation calculation results of interactions force between the TVT derivatives and NH3. These general approach demonstrates that noncovalent interaction could greatly affect its sensor capability and offer a new thought for design of high perofrmance gas sensing materials.

IMMOBILIZATION OF LEVOTHYROXINE IN QUATERNIZED N,N-DIETYL N-METHYL CHITOSAN HYDROGEL AND CHEMICAL NATURE OF THE INTERACTION

Immobilization of a thyroid hormone substitute of L-thyroxine on chitosan-based smart hydrogel structure was performed to reduce the side effects of the required daily dose. The hydrogel was obtained by the Schiff reaction of chitosan with acetaldehyde and quaternization with methyl iodide then by ion exchange with NaCl salt. Finally, a hydrogel was obtained from the treatment of chitosan-based salt at -200C. The amount of levothyroxine immobilized by physical sorption on the hydrogel was determined by molecular electron spectroscopy on basis especially absorption peak at 227 nm. Results of IR- and UV-Vis spectroscopic analyses revealed that the interaction between levothyroxine and hydrogel occurs mainly due to hydrogen bonding and orientation forces of intermolecular interaction

Synthesis of a biobased resin and its screening as an alternative adsorbent for organic and inorganic micropollutant removal.

The sol-gel route was used to synthesize a biophenolic resin from a blend of Kraft black liquor and condensed tannin. The biobased resin has an amorphous structure and diversified surface functional groups. The biomaterial thermal stability was improved by Kraft black liquor, which increased the fixed carbon yield by 19.78% in an oxidant medium and 9.07% in an inert medium. Moreover, the presence of fixed carbon and char is positively related to the material flame retardant property. Additionally, impedance measurements were used to understand the physical phenomena occurring at the polymeric matrix's interface and the material's final properties. The biobased resin characterization and the considerable increase in the presence of micropollutants in surface and water bodies suggest the new biomaterial application in the adsorption process. Thus, its adsorption capacity toward several organic and inorganic micropollutants and its effectiveness in complex water matrices were evaluated. Methylene blue was used as a model compound to assess the influence of the resin composition on the adsorption capacity, and the type H isotherm indicates the high affinity of the biobased resin toward the micropollutant. The adsorption occurs in multilayer by intermolecular interaction and electrostatic forces. The amount of Kraft black liquor favored the adsorption, and the adsorption capacity was greater than 1250mgg-1. When inorganic compounds were evaluated, the carboxyl and phenol groups favor the biomaterial affinity toward metal ions. Cu2+ and Ni2+ were completely removed from the contaminated water, and the adsorption capacity of the other inorganic compounds was: Pb2+ (36.97mgg-1), Al3+ (22.17mgg-1), Ba2+ (12.76mgg-1), Ag1+ (33.85mgg-1), and Fe2+ (19.44mgg-1). In contrast, the adsorption capacity of the organic micropollutants was: 2,4-D (3.09mgg-1), diuron (5.89mgg-1), atrazine (2.71mgg-1), diclofenac (2.04mgg-1), caffeine (5.79mgg-1), acetaminophen (4.80mgg-1), methylene Blue (106.66mgg-1), and methyl orange (30.48mgg-1). The results pointed that the adsorption efficiency of organic micropollutants increases with the distribution coefficient (logD), indicating the biobased resin affinity toward more lipophilic compounds and ionized species.

Coal-CH4/CO2 high-low orbit adsorption characteristics based on molecular simulation

To study the competitive adsorption mechanism of CH4 and CO2, the structural parameters of Tianchi coal were obtained through proximate and ultimate, X-ray photoelectron spectroscopy (XPS), and 13C nuclear magnetic resonance (13C NMR). Then the Tianchi coal molecular structure model was established. Finally, the adsorption of CH4 and CO2 was simulated using Materials Studio (MS). The results show that: (1) The lone electron pairs on the O atoms in CO2 molecules lead to the adsorption to be dominated by electrostatic force. In addition, hydrogen bonds that can increase adsorption are formed between coal and CO2 molecules but not between coal and CH4 molecules. (2) Due to the existence of the intermolecular interaction force, the low (L) orbit is greatly affected by the repulsive force, and the high (H) orbit is less affected by the gravitational force. Therefore, the adsorption mainly occurs in the middle (M) orbit, and the adsorption sites of CO2 on the L and M orbit are more than CH4. (3) The CO2 molecule has a smaller diameter and can enter the ultrafine pores. Hence the accessible solvent pore volume and surface area obtained using CO2 as a molecular probe are greater than those obtained using CH4 molecular.

Effects of inducer type and concentration on the formation mechanism of W/O/W double emulsion gels

Insulin (INS, hydrophilic) and quercetin (Q, hydrophobic) have broad biological benefits; however, their application is limited because of their instability and poor bioaccessibility. Thus, in this study, water-in-oil-in-water (W/O/W) double emulsion gels based on black bean protein–sodium alginate Maillard conjugate-stabilized double emulsions were fabricated using three different inducers. The water holding capacity (WHC), intermolecular interaction forces, INS and Q encapsulation efficiencies (EEs), rheological and textural properties, microstructures, and structures were influenced by both inducer type [CaCl2, glucolactone (GDL), and glutamine transaminase (TGase)] and concentration. The addition of each inducer significantly increased the WHC, INS, and Q EEs, and textural properties of the emulsion gel. Moreover, the rheological behavior analysis showed that all the emulsion gels exhibited marked elastic behavior. These results will help develop an emulsion gel functional carrier based on a black soybean protein–carbohydrate-stabilized W/O/W double emulsion for the targeted and sustained release of drugs.

Combining Renewable Eleostearic Acid and Eugenol to Fabricate Sustainable Plasticizer and Its Effect of Plasticizing on PVC

The recent studies on sustainable plasticizer mainly focus on raw material source, synthesis method and plasticization, but the effect of chemical functional groups (epoxy group and ester group) of sustainable plasticizer on compatibility and thermal stability of plasticized polyvinyl chlorid (PVC) materials has been ignored. In this study, two kinds of sustainable plasticizers (eleostearic acid eugenol ester (EAEE) and epoxidized EAEE) were synthesized to plasticize PVC films using eleostearic acid and eugenol. Compared to EAEE, PVC plasticized with epoxidized EAEE showed more flexible and thermal stability. Due to forming more hydrogen bonds between PVC chains and epoxidized EAEE than that of PVC chains, the efficient plasticizing on PVC with epoxidized EAEE was more than EAEE. Because of the flexible alkane chains and polar group (ester groups and epoxy groups) in the structure of epoxidized EAEE, the intermolecular interaction force with PVC was stronger than EAEE, and there was homogeneous and smooth surface of plasticized PVC films.Graphical Abstract

Effects of the Mixture of Xylooligosaccharides and Egg White Protein on the Physicochemical Properties, Conformation, and Gel-Forming Ability of Culter alburnus Myofibrillar Protein during Multiple Freeze-Thaw Cycles.

This study focuses on the effect of the mixture (XO/EW) of xylooligosaccharides (XO) and egg white protein (EW) on the physicochemical properties, conformation, and gel-forming ability of Culter alburnus myofibrillar proteins (MP) during multiple freeze–thaw (FT) cycles. In our methodology, MP samples added with EW, XO, or XO/EW mixture (1%, v/v) are prepared, and after multiple FT cycles, the XO or XO/EW-treated samples show significant (p < 0.05) inhibition on the decrease of sulfhydryl content and the increase of carbonyl content of MP. Compared with EW, XO or XO/EW could delay the increase of surface hydrophobicity and the decline of secondary and tertiary structural properties of MP, indicating that XO or XO/EW could more effectively increase the stability of MP conformation. Meanwhile, XO/EW could more effectively reduce the decrease of gel strength and gel water holding capacity, and the increase in the T2 relaxation time of MP gel, confirming that XO/EW could substantially improve the MP gel-forming ability. Analysis of intermolecular interaction force proves that, compared with EW, XO/EW could reduce the content decrease of ionic and hydrogen bonds in MP gel. Overall, XO/EW could improve the stability of MP functional properties over multiple FT cycles. This study provides a new perspective for the potential commercial application of EW as a low-calorie cryoprotectant in aquatic products.

Ovalbumin and Kappa-Carrageenan Mixture Suppresses the Oxidative and Structural Changes in the Myofibrillar Proteins of Grass Carp (Ctenopharyngodon idella) during Frozen Storage.

This study was done to analyze the cryoprotective influence of ovalbumin (OVA) with kappa-carrageenan (KC) in grass carp myofibrillar proteins during frozen storage. Ca2+-ATPase activity of MP was significantly reduced due to protein denaturation and showed a direct association with decreased sulphydryl (SH) contents and tertiary structural properties. Besides that, an increase in carbonyl, surface hydrophobicity, and dityrosine contents was observed. The addition of OVA-KC significantly restricted the decline in Ca2+-ATPase and SH groups, which were further confirmed by the retarded increase in carbonyls. Furthermore, the addition of OVA-KC increased the stability of α-helix contents. Moreover, MP treated with 6% OVA-KC also improved intermolecular interaction forces linked with gelling and water holding properties of MP. Therefore, it can be concluded that OVA-KC could be used as an effective cryoprotectant in fish and related products for preservation and commercialization.

On Developing a Hydrophobic Rubberized Cement Paste.

It is well known that most cement matrix materials are hydrophilic. For structural materials, hydrophilicity is harmful because the absorption of water will induce serious damage to these materials. In this study, crumb rubber was pretreated by partial oxidation and used as an additive to develop a hydrophobic rubberized cement paste. The pretreated crumb rubber was investigated using Fourier-transform infrared spectrometry (FT-IR) to understand the function groups on its surface. The pyrolysis oil adsorbed on the surface of the crumb rubber was observed by FT-IR and nuclear magnetic resonance (NMR) spectroscopy. A colloid probe with calcium silicate hydrate (C–S–H) at the apex was prepared to measure the intermolecular interaction forces between the crumb rubber and the C-S-H using an atomic force microscope (AFM). Pure cement paste, cement paste with the as-received crumb rubber, and cement paste with pretreated crumb rubber were prepared for comparison. FT-IR, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to understand the microstructure of the pastes. The static contact angle was used as the index of the hydrophobicity of the pastes. Experimental results showed that the hardened cement paste containing partially oxidized crumb rubber had excellent hydrophobic properties with an insignificant reduction in the compressive strength.