Inorganic Calcium Carbonate Research Articles

Calcium carbonate-based antibacterial coating for improved biocompatibility in endoprosthetic implants

This article addresses a critical challenge in modern endoprosthetics: enhancing the biocompatibility of implanted materials to prevent and manage periprosthetic infec-tions. Current literature identifies periprosthetic infection as a leading cause of revision surgeries, with material incompatibility contributing to postoperative complications and increased mortality rates. To tackle this issue, a specialized coating for implant surfaces based on inorganic calcium carbonate is proposed. This material is selected for its fa-vorable biochemical properties, including a highly developed specific surface area and biocompatibility with human tissues. To enhance antibacterial properties, zinc and the antibiotic vancomycin are incorporated as modifiers. Research efforts have led to the development of a 3D model of an elbow joint endoprosthesis, ensuring reliable fixation within the bone structure. The stress-strain characteristics of the endoprosthesis are examined, determining safety margins for its components. A biocompatible coating com-posed of calcium carbonate is synthesized and modified with antibacterial agents. Imag-es of the coating's microparticles are obtained, and a biochemical analysis is performed using common postoperative pathogens, revealing zones of microorganism suppres-sion. The findings confirm an improved biocompatibility level, demonstrating the effec-tive antibacterial properties of the developed coating, with promising implications for preventing periprosthetic infections.

Effect of environmentally friendly reverse osmosis scale inhibitors on inorganic calcium carbonate scale

A highly efficient and environmentally friendly composite scale inhibitor was developed using sodium carboxymethyl cellulose (CMC-Na) and polyepoxysuccinic acid (PESA). The PESA:CMC-Na=1:3 optimum ratio was observed with a maximum enhancement factor of 1.81. The film flux attenuation rate was reduced from 24.98 % to 6.2 % at optimal operational condition (concentration 80 mg/L, initial pH 7) for actual mine water treatment. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis results showed that the addition of the compound scale inhibitor transformed the calcium carbonate scale from calcite to vaterite with looser and more porous structure. The molecular dynamics simulation results demonstrate that composite scale inhibitor had a higher binding energy with calcite than that of PESA, CMC-Na, resulting in the restrained formation of calcite. This study provides a new technical idea for the application of scale inhibitor to improve the treatment efficiency of mine water by reverse osmosis.

Effect of Calcium Carbonate as Filler on the Physicomechanical Properties of Polypropylene Random

To minimize the cost of production and enhancement pipe quality, this research aims to gain insights into the physical and mechanical characteristics of high-performance polypropylene random filled with rigid inorganic calcium carbonate particles at various content levels, with a specific focus on how the toughness of PPR changes. Virgin Polypropylene Random PPR, a new material extracted from a homopolymer polypropylene, is used as a matrix with 10, 20, 30, 40, and 50 wt. % of CaCO3. The density, melt flow rate, tensile strength, tensile strain, modulus of elasticity, and hardness are used to evaluate the quality of the material. The results showed that the density, the modulus of elasticity, and the hardness increased with increasing the percentage of CaCO3. As the percentage of CaCO3 increased, the melt flow rate decreased. The tensile strength and strain increased to 28.7 MPa and 533.25%, respectively at 20 wt.% of CaCO3, with 14.8% and 6.65% reaching gains compared to the virgin PPR (25 MPa and 500%). The enhancement of the mechanical properties is thanks to the presence of stiffer and rigid particles of CaCO3 that act as a reinforcing agent. Moreover, when CaCO3 is well dispersed, it forms a strong bond with the polypropylene matrix, and facilitates the transfer of stress from the matrix to the fillers, resulting in increased stiffness. The optimum percentage of CaCO3 to add into the inner layer of extruded PPR pipes is at a composition of the filler of 20 wt. %.

Preparation of PW@CaCO3 phase change microcapsules modified by ZnO nanoparticles with excellent photocatalytic and thermal properties

We utilized an in-situ polymerization method to dope zinc oxide (ZnO) nanoparticles onto the surface of the inorganic calcium carbonate (CaCO3) shell capable of encapsulating paraffin wax (PW) cores, and synthesized a novel bifunctional microcapsule, which can be applied to optical catalysis and thermal energy storage. The PW@CaCO3/ZnO microcapsules with the varying ZnO nanoparticles were successfully synthesized. The micromorphology, chemical components, thermal properties, and photocatalytic applications of microcapsules doped with various ZnO concentrations were investigated. The results indicated that the PW@CaCO3/0.03%ZnO (i.e., the mass ratio of ZnO to PW of 0.03 wt%) exhibited the greatest thermal storage effectiveness and capacity with regard to all the samples. Under exposure to a particular wavelength of ultraviolet light, the PW@CaCO3/ZnO microcapsules can degrade the methylene blue dye solution by photocatalysis. The photocatalytic effect of the dye solution with PW@CaCO3/1.50%ZnO was the best after 12 h of exposure to ultraviolet radiation, and the degradation rate reached 98.97 %. In the spheres of energy conservation and environmental preservation, the PW@CaCO3/ZnO microcapsules offer a wide range of potential applications.

The Possibility of Using Bee Drone Brood to Design Novel Dietary Supplements for Apitherapy

Drone brood is a little-known bee product, often treated as beekeeping waste or natural varroosis bait. Obtaining drone brood from beehives does not weaken the bee family, which is why this product is used as natural medicine in Eastern European countries. The main objective of this work was to design an innovative dietary supplement containing freeze-dried drone brood (DB) enriched with calcium ions (3:1). As the calcium component, inorganic calcium carbonate (CC) and ground chicken eggshells (ES) were used. Bioaccessibility of hormones, selected nutrients (proteins and amino acids), non-nutritive polyphenols from pure drone brood (DB), and designed supplements (DB + CC, DB + ES) were analyzed using an in vitro gastrointestinal system. It was shown that drone brood components are better bioaccessible from the DB + ES compared to DB + CC and DB capsules. An increase was achieved by up to 93.33%, 21.29%, 105.14%, and 52.34% for testosterone, estradiol, calcium, and polyphenols, respectively. Drone brood proteins were completely digested to free amino acids which was confirmed by SDS-PAGE electrophoresis and high-performance thin layer chromatography (HPTLC). Due to the demonstrated synergistic action of drone brood and the calcium of eggshells, the newly proposed two-ingredient supplement seems to be an efficient treatment to equalize hormonal and calcium deficiency in osteoporosis; however, its application requires further studies.

Thermal Energy Storage Performance Enhancement of Microencapsulated n-Tetracosane with a Polymorph-Modulated Calcium Carbonate Shell

Microencapsulated n-tetracosane as a phase change material with an inorganic calcium carbonate (CaCO3) shell has been synthesized through a self-assembly process with varying pH value of a precursor solution, and the resultant materials were systematically investigated. Spherical microcapsules with a mean diameter of less than 3 μm were seen by microscopic observation. X-ray diffraction analysis revealed the presence of three CaCO3 polymorphs such as calcite, aragonite, and vaterite in the shell, and these compositions depended on the solution pH. This fact was also confirmed by Fourier transform infrared spectra and reflected in the surface morphology of microcapsules. The characterization of the phase change behavior has shown no significant change in the phase change temperatures and more than 170 mJ/mg of phase change enthalpies with the microcapsules synthesized at pH = 1. This enthalpy corresponds to 69.2% of encapsulation efficiency which is improved from the value reported by other microcapsules with CaCO3 shells. Thermal cycling analysis exhibited good reliability and durability of phase change phenomena in the long term. These results demonstrate a promising potential of microcapsules for developing thermal energy storage materials at a mild temperature range, which can be applied for waste heat recovery applications.

Mechanical Properties of Post-Cured Eggshell-Filled Glass-Fibre-Reinforced Polymer Composites

Eggshells are a potentially polluting industrial waste that are disposed of as landfill which has proven to be hazardous to the environment. The usage of chicken eggshells as a biofiller for polymer matrix composites instead of its disposal as landfill has proven advantageous in various studies. On the other hand, using eggshells as a filler material to replace inorganic calcium carbonate usage would be another environment friendly act. The present study is focused on studying the effects of eggshell filler addition and post-curing on polymer composites which could be utilised for domestic applications. Herein, uncarbonised and carbonised eggshell filler material were processed from waste eggshells. Hybridisation of the carbonised and uncarbonised eggshell filler was carried out. All three variants of eggshell fillers (10 wt.%) were used in the fabrication of composites. A hand lay-up technique was employed in the fabrication of unfilled composites along with three variants of filled composites, namely, uncarbonised, carbonised, and hybrid eggshell filled composites. The fabricated and cured composites were further subjected to post-curing at a temperature of 60 °C for a period of 2 h. All four variants of post-cured composites were then subjected to mechanical testing according to American Society for Testing and Materials (ASTM) standards. The tests revealed that all three variants of filled composites possess better mechanical properties in comparison with unfilled composites. Further, in comparison with unfilled composites, the carbonised eggshell filled composites showcased 42% and 49% improvement in flexural and tensile properties, respectively. The modes of failure of the specimens were observed and tabulated. SEM imaging revealed that the eggshell filler contributed to the strengths of the composites by means of arresting and deviating cracks. It was also observed that the post-cured specimens displayed improved properties when compared with our previous studies on non-post-cured specimens. In summary, the study showcased the benefits of eggshell filler addition and the post-curing of polymer composites.

A Primary Study on Mechanical Properties of Heat-Treated Wood via in-situ Synthesis of Calcium Carbonate

This study aims to improve the value of fast-growing wood and extend the heat-treated wood utilization using inorganic calcium carbonate (CaCO3) crystals via an in-situ synthesis method. CaCl2 and Na2CO3 solutions with a concentration ratio of 1:1 were successively introduced into the thermally modified poplar wood obtained by steam heat treatment (HT) at 200°C for 1.5 and 3 h, resulting in the in-situ synthesis of CaCO3 crystals inside the heat-treated wood. The filling effect was best at the concentration of 1.2 mol/L. CaCO3 was uniformly distributed in the cell cavities of the heat-treated wood, and some of the crystals were embedded in the fissures of the wood cell walls. The morphology of CaCO3 crystals was mainly spherical and rhombic polyhedral. Three main types of CaCO3 crystals were calcite, vaterite, and aragonite. The HT of poplar wood at 200°C resulted in degrading the chemical components of the wood cell wall. This degradation led to reduced wood mechanical properties, including the surface hardness (HD), modulus of rupture (MOR), and modulus of elasticity (MOE). After CaCO3 was in-situ synthesized in the heat-treated wood, the HD increased by 18.36% and 16.35%, and MOR increased by 14.64% and 8.89%, respectively. Because of the CaCO3 synthesization, the char residue of the 200°C heat-treated wood samples increased by 9.31% and the maximum weight loss rate decreased by 19.80%, indicating that the filling with CaCO3 cannot only improve the mechanical properties of the heat-treated wood but also effectively enhance its thermal stability.

Effect of surfactants on encapsulation of hexadecane phase change material in calcium carbonate shell for thermal energy storage

Microencapsulation of hexadecane core, an organic phase change material using inorganic calcium carbonate shell was carried out through self-assembly technique. The microcapsules prepared with mixed surfactants sodium dodecyl sulfate/non-polar polyvinylpyrrolidone (1:1 mass ratio) and core/shell of 1:1 mass ratio were found to produce spherical morphology observed from Field emission scanning electron microscope images. Fourier transform infrared analysis established no interaction between core and shell, while Energy dispersive X-ray spectrometer ensured presence of calcium carbonate. Latent heat of phase transformations, melting/crystallization temperatures, and encapsulation efficiency parameters were obtained from Differential scanning calorimetry, while Thermogravimetry analysis indicated the temperature range of its applicability. Latent heat of melting and corresponding encapsulation efficiencies estimated with varying core/shell mass ratios were between 59.48 J·g−1–95.92 J·g−1 and 26.85 %–43.12 %, respectively. Sample with equal amount of core/shell (1:1) was found to best microcapsules based on morphology and latent heat value. Encapsulation efficiency obtained from thermogravimetry analysis was consistent with those noted from differential scanning calorimetry. 100 thermal cycles (0 to 30 °C) indicated appreciable stability with temperature fluctuations, which may be useful as a cheap energy storage material in textile applications.

Hard, Soft, and Hard-and-Soft Drug Delivery Carriers Based on CaCO3 and Alginate Biomaterials: Synthesis, Properties, Pharmaceutical Applications.

Because free therapeutic drug molecules often have adverse effects on normal tissues, deliver scanty drug concentrations and exhibit a potentially low efficacy at pathological sites, various drug carriers have been developed for preclinical and clinical trials. Their physicochemical and toxicological properties are the subject of extensive research. Inorganic calcium carbonate particles are promising candidates as drug delivery carriers owning to their hardness, porous internal structure, high surface area, distinctive pH-sensitivity, low degradability, etc, while soft organic alginate hydrogels are also widely used because of their special advantages such as a high hydration, bio-adhesiveness, and non-antigenicity. Here, we review these two distinct substances as well as hybrid structures encompassing both types of carriers. Methods of their synthesis, fundamental properties and mechanisms of formation, and their respective applications are described. Furthermore, we summarize and compare similarities versus differences taking into account unique advantages and disadvantages of these drug delivery carriers. Moreover, rational combination of both carrier types due to their performance complementarity (yin-&yang properties: in general, yin is referred to for definiteness as hard, and yang is broadly taken as soft) is proposed to be used in the so-called hybrid carriers endowing them with even more advanced properties envisioned to be attractive for designing new drug delivery systems.

Conversion of soybean oil extraction wastes into high-performance wood adhesives based on mussel-inspired cation-π interactions

As a soybean oil extractive byproduct, high temperature defatted soy meal (HSM) presents great potential as a raw material for vegetable protein adhesives to replace aldehyde-based adhesives in the wood-based panel production. However, the application has been hindered by its poor cold-pressing adhesive performance. Herein, a novel HSM-based adhesive with excellent cold-pressing adhesion performance was developed based on mussel-inspired cation−π interactions. Highly reactive polyamidoamine-epichlorohydrin (PAE) and folic acid (FA) were added into an HSM-based adhesive to construct a dual-network system stabilized by strong cation−π interactions. The coacervate formed by PAE and FA served as an “internal adhesive” to bond HSM particles together, yielding high initial viscosity but easy sizing. As expected, the prepared adhesive exhibited an excellent cold-pressing bonding strength of 423 kPa, showing a 295% improvement compared to the soy protein (SP) adhesive. To improve the hot-pressing bonding strength of the adhesives, inorganic calcium carbonate (CaCO3) particles were introduced into the adhesive system to build an organic–inorganic hybrid adhesive system. The wet shear strength of the SPAE-FA-CaCO3 adhesive significantly improved from 0.63 MPa to 0.96 MPa, meeting the requirements for the practical application. This method provides a novel strategy to exploit high-performance vegetable protein-based wood adhesives.

Giant ooids of microbial origin from the Zhangxia Formation (Cambrian Miaolingian Series) in North China

The role of microorganisms in the formation of giant ooids is one of the areas of long-term controversy in ooidal research, but it has not been confirmed conclusively. Abundant giant ooids developed in the Zhangxia Formation of the Cambrian Miaolingian Series in North China. Giant ooids in the study area were examined by using Polarized Light Microscopy and Field Emission Environmental Scanning Electron Microscopy. The nuclei of the ooids consist of micritic pellets or radial ooids with diameters less than 2 mm and are formed in a weak-agitating seawater environment. Their cortices are concentric, and are characterized by the alternations of the dark laminae of micritic calcite or Girvanella filaments and light laminae of microsparry calcite. In the environments of inter-bank sea with the alternating development of medium and low energy and chiefly weak-agitating conditions, giant ooids were formed under the joint action of Girvanella filamentous growth, biologically-induced calcification and/or biologically-influenced calcification and inorganic calcium carbonate precipitation. The microfossils of Girvanella are distributed in inner and outer cortices of giant ooids, especially dense in the latter. This distinctly indicates that microbes play a significant role in the formation of giant ooids, and also provides a vital example for discussing the microbial origin of giant ooids.

Chicken eggshell powder more effectively alleviates bone loss comparted to inorganic calcium carbonate: an animal study performed on ovariectomized rats.

This study aimed to evaluate the effects of chicken eggshell powder rich in calcium and the inorganic form of calcium carbonate on osteoporotic bone structure using an animal model of ovariectomized rats. Animals were divided into four groups: sham-operated rats (SHAM group); ovariectomized rats untreated (OVX group); OVX rats treated with eggshell powder (Biomin H® OVX + ECa group; total Ca content 1.5%); and OVX rats receiving inorganic calcium carbonate (calcium carbonate precipitated, total Ca content 1.5%; OVX + ICa group) during 8 weeks. Ovariectomy increased total body weight, plasma alkaline phosphatase activity, cortical bone thickness, periosteal bone apposition, and considerably worsened the trabecular bone microarchitecture. Calcium supplementation in both OVX + ECa and OVX + ICa groups elevated blood supply in the cortical bone when compared to OVX rats. Treatment with eggshell powder, unlike the OVX + ICa group, significantly lowered bone resorption, increased plasma calcium level, relative volume of trabecular bone, and secondary osteon population density, which together contributes to the enhanced bone strength. In addition, sizes of Haversian canals and secondary osteons in OVX + ECa group reached the values of SHAM group. Our results suggest that chicken eggshell powder more effectively ameliorates bone loss in ovariectomized rats than precipitated calcium carbonate.

Processing and Characterization of Surface Treated Chicken Eggshell and Calcium Carbonate Particles Filled High-Density Polyethylene Composites

Abstract The use of the biowaste chicken eggshell (ES) particles as an alternative filler for the inorganic calcium carbonate (CC) in polymeric materials was investigated in this study. ES and CC were chemically surface treated with stearic acid by dry and wet methods. Composites of ES and CC filled high-density polyethylene (HDPE) was prepared via melt mixing and their thermal-mechanical- and flow behavior was characterized. FTIR results showed some changes in the chemical structure of SA treated ES and CC. The mechanical properties of the composites fluctuated in their values based on the SA treatment method. The wet-treated HDPE/ES composites showed higher tensile and flexural strengths compared to that of the untreated ones which were also higher than their counterparts of HDPE/CC composites. The treated-ES particles motivated the crystallization process of HDPE compared to the untreated-ES and better flow properties was reported for composites with higher crystallinity and for HDPE/CC composites. Morphological observations showed particles agglomeration and void existence which led to deterioration of the mechanical properties.

Coccolithophore calcification studied by single-cell impedance cytometry: Towards single-cell PIC:POC measurements

Since the industrial revolution 30% of the anthropogenic CO2 is absorbed by oceans, resulting in ocean acidification, which is a threat to calcifying algae. As a result, there has been profound interest in the study of calcifying algae, because of their important role in the global carbon cycle. The coccolithophore Emiliania huxleyi is considered to be globally the most dominant calcifying algal species, which creates a unique exoskeleton from inorganic calcium carbonate platelets. The PIC (particulate inorganic carbon): POC (particulate organic carbon) ratio describes the relative amount of inorganic carbon in the algae and is a critical parameter in the ocean carbon cycle.In this research we explore the use of microfluidic single-cell impedance spectroscopy in the field of calcifying algae. Microfluidic impedance spectroscopy enables us to characterize single-cell electrical properties in a non-invasive and label-free way. We use the ratio of the impedance at high frequency vs. low frequency, known as opacity, to discriminate between calcified coccolithophores and coccolithophores with a calcite exoskeleton dissolved by acidification (decalcified).We have demonstrated that using opacity we can discriminate between calcified and decalcified coccolithophores with an accuracy of 94.1%. We have observed a correlation between the measured opacity and the cell height in the channel, which is supported by FEM simulations. The difference in cell density between calcified and decalcified cells can explain the difference in cell height and therefore the measured opacity.

Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord

Environmental change can have a significant impact on biogeochemical cycles at high latitudes and be particularly important in ecologically valuable fjord ecosystems. Seasonality in biogeochemical cycling in a sub-Arctic fjord of northern Norway (Kaldfjorden) was investigated from October 2016 to September 2018. Monthly changes in total inorganic carbon (CT), alkalinity (AT), major nutrients and calcium carbonate saturation (Ω) were driven by freshwater discharge, biological production and mixing with subsurface carbon-rich coastal water. Stable oxygen isotope ratios indicated that meteoric water (snow melt, river runoff, precipitation) had stratified and freshened surface waters, contributing to 81% of the monthly CT deficit in the surface layer. The timing and magnitude of freshwater inputs played an important role in Ω variability, reducing AT and CT by dilution. This dilution effect was strongly counteracted by the opposing effect of primary production that dominated surface water Ω seasonality. The spring phytoplankton bloom rapidly depleted nitrate and CT to drive highest Ω (~2.3) in surface waters. Calcification reduced AT and CT, which accounted for 21% of the monthly decrease in Ω during a coccolithophore bloom. Freshwater runoff contributed CT, AT and silicates of terrestrial origin to the fjord. Lowest surface water Ω (~1.6) resulted from organic matter remineralisation and mixing into subsurface water during winter and spring. Surface waters were undersaturated with respect to atmospheric CO2, resulting in modest uptake of –0.32 ± 0.03 mol C m–2 yr–1. Net community production estimated from carbon drawdown was 14 ± 2 g C m–2 yr–1 during the productive season. Kaldfjorden currently functions as an atmospheric CO2 sink of 3.9 ± 0.3 g C m–2 yr–1. Time-series data are vital to better understand the processes and natural variability affecting biogeochemical cycling in dynamic coastal regions and thus better predict the impact of future changes on important fjord ecosystems.

Isotope sclerochronology of ammonites (Baculites Compressus) from methane seep and non-seep sites in the Late Cretaceous Western Interior Seaway, USA: Implications for ammonite habitat and mode of life

Ammonites, as well as other fauna, were common in methane seeps of the Late Cretaceous Western Interior Seaway (WIS) of North America. Biogeochemical processes at the seeps, in particular the anaerobic oxidation of methane, produced a dissolved inorganic carbon reservoir with a low δ13C, manifested in the carbon isotope composition of the inorganic calcium carbonate concretions associated with the seeps and recorded in well-preserved shells of ammonites documented at the sites. Detailed sclerochronological sampling of six well-preserved specimens of Baculites compressus collected at seep sites in the Pierre Shale of South Dakota reveals three patterns that can be explained by reference to two specimens of the same species collected at age-equivalent non-seep sites. Three of the specimens exhibit uniformly low values of δ13C that are significantly different (unpaired t-test, p

Surface modification of polyacrylonitrile ultrafiltration membranes using amphiphilic Pluronic F127/CaCO3 nanoparticles for oil/water emulsion separation

In this work, flat sheet polyacrylonitrile (PAN) based ultrafiltration (UF) membranes were fabricated by blending with amphiphilic copolymer Pluronic F127 (PF127) and inorganic calcium carbonate (CaCO3) nanoparticles by nonsolvent induced phase inversion process which was employed as fouling resistant membranes for the separation of oil-water emulsion mixture. CaCO3 nanoparticle was synthesized by controlled precipitation of saturated carbonate and calcium nitrate aqueous solution and was then confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD) and high-resolution transmission electron microscopy (HR-TEM). The fabricated membranes were characterized by attenuated total reflectance infrared spectroscopy (ATR-FTIR), thermal gravimetric analysis (TGA), mechanical analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM) analysis to study the effect on the addition of PF127 together with varying amount of CaCO3 nanoparticle dosage on the membrane property. The filtration performances of the membranes were evaluated by measuring pure water flux, molecular weight cut off (MWCO), porosity and water content. The membrane hydrophilicity/hydrophobicity was examined through water contact angle measurement and separation efficacy was measured through ultrafiltration of oily feed solution. Membrane properties such as wettability, pure water permeability, mechanical strength, thermal stability, oil removal efficiency of the modified membrane was found to increase high upon addition of 0.75wt% of CaCO3 nanoparticle. Flux recovery was found to elevate from around 63% to 90% after a simple hydraulic wash indicating that the modified hybrid membranes were less susceptible to fouling. The increase in water permeability and antifouling property is ascribed the presence of large number of hydroxyl functional groups coupled with large number of small pores on the modified membrane surface.

Superhydrophobic Paper by Facile and Fast Atmospheric Pressure Plasma Etching

Superhydrophobic and to some extent oleophobic paper surfaces are prepared using atmospheric pressure plasma etching. A novel dielectric barrier discharge operating in helium–oxygen mixture is used to rapidly etch organic material from paper surface and create hierarchical topography and subsequently a thin fluorocarbon film is deposited to modify the surface energy. The enhancement of surface topography is achieved via the selective removal of organic matter over inorganic calcium carbonate (calcite) fillers that co-exist in paper. The process led to the fabrication of roll-off superhydrophobic paper with water contact angles >150° and hysteresis <10° for all samples treated over 2 min with no deterioration of paper quality. Further treatment over 8 min resulted also in diiodomethane repellent surfaces.

Fabrication of raspberry-like polymethylsilsesquioxane microspheres mediated by tinny calcium carbonate particles

The particle formation behavior of methyltrimethoxysilane (MTMS) was researched in the presence of a small amount of inorganic calcium carbonate particles. MTMS was first hydrolyzed in water under the catalyzation by hydrochloric acid to produce hydrolyzate and then neutralized by base sodium hydroxide. Under the neutral condition, the hydrolyzate of MTMS was mixed with a small amount of newly-prepared precipitation of calcium carbonate. Following this, hydrolytic polycondensation reaction catalyzed by adding ammonia to the mixture was conducted. The results show that polymethylsilsesquioxane (PMSQ) particles with raspberry-like morphology were obtained by this method, while those without addition of calcium carbonate are of smooth surface, which was confirmed by scanning electron microscopy (SEM) micrographs. The static water contact angles changed from 136.2±0.9° of pure PMSQ particles with smooth surface to 146.3±1.1° with raspberry-like morphology, showing a great increment in apparent hydrophobicity.