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The SEM micrograph of the pure polyaniline prepared by the polymerization of aniline monomer using ammonium persulafte as an oxidant at room temperature. The white scale bar indicates 1 lm
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Synthesis and characterization of a new cement-based polymer nanocomposite is reported. Calcium silicate hydrate (C–S–H) was
prepared in the presence of aniline monomer followed by in situ polymerization to increase the degree of interaction between
inorganic and organic phases. Two stoichiometrically different C–S–H systems were used. The properti...
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Transmission electron microscopy and related analytical techniques have been widely used to study the microstructure of different materials. However, few research works have been performed in the field of glasses, possibly due to the electron-beam irradiation damage. In this paper, we have developed a method based on electron energy loss spectrosco...
Citations
... Therefore, there is an urgent need for a dispersant to assist CSH to achieve uniform dispersion. The addition of polymer during the process of synthesizing CSH by co-precipitation is considered to be an excellent solution for the agglomeration problem [7][8][9][10][11]. ...
... The examples of organic-inorganic coupling in C-S-H's molecular structure and texture have increasingly been reported in the cement chemistry literature [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. However, most of these studies are concerned with the examination of polymer intercalation vs. adsorption of various organic molecules on its surface, as discussed in [29]. ...
We study the conductive heat transport through calcium silicate hydrate (C-S-H) and organically cross-linked C-S-H via experiments, micromechanical homogenization theory, and molecular simulations. We find that C-S-H's intrinsic thermal conductivity falls below its amorphous limit when cross-linked with short-chain organosilanes. The observed reduction correlates with the alkyl chain length of the bis-organosilane molecule. To understand the underlying fundamental molecular processes accountable for such a reduction, we construct realistic molecular structures of cross-linked C-S-H and validate them against the spectroscopic and pycnometery measurements. The atomistic simulations indicate that the reduction in the contribution of propagons (propagating heat carriers) and diffusons (diffusive heat carriers) to heat transport, and the amplification of locons (localized vibrational modes), are the main driving factors allowing to limit the heat conduction in C-S-H. Presented findings offer new potential directions to nanoengineering novel admixtures for cement composites and resilient lightweight cementitious mesostructures for thermally efficient building envelopes.
... Alizadeh et al. also incorporated aniline during the synthesis of C-S-H based on the reaction between calcium oxide and silica in water and the resultant C-S-H/aniline composite was further subjected to the reaction with ammonium persulfate, thereby prompting homopolymerization of aniline (Alizadeh et al., 2010). This two-step process, where compositing C-S-H with organic monomer was followed by polymerization, resulted in the formation of C-S-H/polyaniline composite. ...
Nature-inspired ensemble of organic and inorganic constituents, such as that found in the microstructure of nacre and dactyl clubs of Mantis shrimp, has evolved into the model system for the structural design of industrial composites. This novel design concept, which helps attaining the balance between strength, toughness and ductility, has not only induced a paradigm shift in the synthesis of advanced materials such as graphene-based composites but also, in the development of more abundant, low-cost materials such as cement and concretes. The advance in synthetic techniques and the advent of new manufacturing technologies such as 3D printing has enabled effective integration of cementitious materials with soft materials across various length scales. Furthermore, novel functional properties such as self-healing have also been materialized based on a variety of strategies. This review will provide the comprehensive overview on the ongoing research efforts, encompassing 3D printing, self-healing strategies and integration of C-S-H with organic components, all of which are actively exploited in synthesizing bioinspired, multifunctional cementitious materials.
... C-S-H/aniline samples were synthesized in a similar way described above, except for the addition of aniline into the deionized water. The mass content of aniline with respect to the total mass of the solids (CaO + SiO 2 ) was determined to be 3%, according to the previous research [43]. Since aniline has a low solubility in the water, careful agitation was implemented to obtain a well-dispersed aniline aqueous solution before the mixing of the solids and liquids. ...
... 1 g dried C-S-H/aniline sample and 0.45 g ammonium persulfate were mixed with the 200 mL water in a polypropylene container, after which careful agitations were carried out to guarantee a homogenized reaction. The reaction time is determined to be 24 h [43], and afterwards, the C-S-H/polyaniline solid was centrifuged and washed out twice in a glove box filled with nitrogen gas, and then transferred to a vacuum oven for 72 h drying. Finally, the C-S-H/polyaniline sample were stored in a vacuum desiccator until measurements. ...
The composite of organic and inorganic phases is a promising design to create higher performance cement-based materials. In this work, with aniline monomers mixed with synthetic calcium silicate hydrate (C–S–H) gels and then in-situ polymerized, we investigated the influence of this organic modification on the structure and mechanical properties of C–S–H with different calcium to silicon ratios (C/S). Scanning electron microscopy (SEM) images and nano indentation results show the addition of aniline lowers the packing density of C–S–H particles with C/S = 0.7 at meso-scale, and thus causes a substantial fall in the indentation modulus. However, the slower creep rate of C–S–H/aniline indicates aniline monomers may situate in the midst among particles to obstruct the translation between neighboring calcium silicate sheets. For C–S–H samples with C/S = 1, the organic modification occurs at a smaller length scale. X-ray diffraction (XRD) spectra suggest the relatively ordered packing of (0 0 2) crystal plane is strongly disturbed by the incorporation and in-situ polymerization of aniline monomers. Nuclear magnetic resonance (NMR) patterns also prove a nano-structural reorganization of silicate tetrahedra takes place in C–S–H/polyaniline. The interaction mechanisms interpreted here may give solutions to enhancing properties of civil engineering materials by organic modification.
... The change in the interlayer distance of the control and modified C-S-H was examined using XRD. XRD is particularly effective in characterizing materials with layered structure and has been successfully utilized in studying cement-based materials 11,15,45 . The change in the interlayer distance of C-S-H was evaluated by measuring the change in the reflection peak corresponding to 002 basal spacing. ...
... FTIR was used to study the polymerization of silicate chains in C-S-H nanocomposites. In this method, the characteristic stretching vibrations of (Si-O) bonds was used to identify different silicate bonds present in C-S-H 15,18,19 . The presence and intensity of the bridging silicate tetrahedra (Q 2 ) and end silicate tetrahedra (Q 1 ) can be detected using the FTIR spectra. ...
... It is observed that the location of the Q 2 band is shifted towards higher frequencies in the control sample with a reduction in C/S ratio. This is an indication of increased polymerization in the control sample with a C/S of 0.7 compared to the sample with C/S of 1.5 as it is also evident from the higher intensity ratio of Q 2 to Q 1 at the lower C/S 15,60 . It is seen that the location of the Q 2 band in arginine sample at C/S of 0.7 is lower than that of the control C-S-H, suggesting a reduction in polymerization as a result of interaction between arginine and C-S-H at this C/S ratio. ...
Inspired by nature, this paper investigates the effect of biomolecules, such as amino acids and proteins, on the nanostructure and mechanical stiffness of calcium-silicate-hydrate (C-S-H). Amino acids with distinct functional groups, and proteins with different structures and compositions were used in the synthesis of the C-S-H nanocomposite. The atomic structure was examined using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The morphology was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). AFM nanoindentation was used to evaluate the Young's modulus of the modified C-S-H. Positively charged, H-bond forming and hydrophobic amino acids were shown to influence the atomic structure of C-S-H. The effect of negatively charged amino acid on atomic structure was more pronounced at higher C/S ratio. A noticeable increase in silicate polymerization of C-S-H modified with proteins at high C/S ratio was observed. The microscopic examination demonstrated a globular morphology for all samples except for C-S-H modified with hemoglobin, which showed a platelet morphology. The Young's modulus of C-S-H with amino acids and proteins showed a general reduction compared to that of the control C-S-H.
... Calcium-silicate-hydrate (CSH) is the primary phase of hydration product and directly affects the strength and durability properties of cementitious materials [3][4][5][6]. There is an increasing interest in innovative approaches to manipulate the structure of CSH at the nanoscale as a way to influence the macroscale properties [7][8][9][10][11][12][13][14][15]. Use of organic additives to modify the nanostructure of CSH holds potential as a viable approach to influence the properties of CSH. ...
... This approach is inspired by the microstructure of certain biological nanocomposites, such as bones, teeth and the nacre of abalone shells, which exhibit superior engineering performance compared to traditional materials [16,17]. Researchers have studied the possibility of modifying the structure of CSH with polymers [7][8][9][11][12][13][14][15]18,19]. Matsuyama et al. [7][8][9] investigated the possibility of intercalation of polymers with different charges into the structure of CSH with various calcium to silicate (C/S) ratios. ...
... Khoshnazar et al. [14,20,21] studied the characteristics of CSH modified with nitrobenzoic acid and aminobenzoic acid. Alizadeh et al. [12] achieved CSH/polyaniline nanostructures by polymerizing the aniline monomer in the synthesized CSH/aniline complex. Minet et al. [18] reported that small molecular-sized organic molecules can intercalate between the CSH layers without changing the structural framework of CSH. ...
Calcium-silicate-hydrate (CSH)/polymer nanocomposites were synthesized with the layer-by-layer (LBL) method, and their morphology and mechanical properties were investigated using atomic force microscopy (AFM) imaging and AFM nanoindentation. Different sets of polymers were used to produce CSH/polymer nanocomposites. The effect of different factors including dipping time, calcium to silicate ratios (C/S ratios) and pH on morphology was investigated. CSH/polymer nanocomposites made with different sets of polymers showed variation in morphologies. However, the Young’s modulus did not seem to reveal significant differences between the nanocomposites studied here. In nanocomposites containing graphene oxide (GO) nanosheet, an increase in the density of CSH particles was observed on the GO nanosheet compared to areas away from the GO nanosheet, providing evidence for improved nucleation of CSH in the presence of GO nanosheets. An increase in roughness and a reduction in the packing density in nanocomposites containing GO nanosheets was observed.
... [19][20][21][22] The majority of recent research on polymermodified cementitious composites have been limited to develop more effective techniques to enhance organo-mineral interactions. 15,18,[23][24][25] This is in part due to a limited understanding of the cement structure and its chemistry and in part because of the complex interaction mechanisms of organicinorganic phases in polymer cementitious materials. 26 As successful characterizations and experimental probes are becoming available, 27,28 computational methods can provide key insights into understanding and optimizing the intercalation of the organic phase with the inorganic matter. ...
Hybrid materials such as biomimetic platelet-matrix composites are in high demand to confer low weight and multifunctional mechanical properties. This letter reports interfacial-bond regulated assembly of polymers on cement-an archetype model with significant infrastructure applications. We demonstrate a series of 20+ molecular dynamics studies on decoding and optimizing the complex interfacial interactions including the role and types of various heterogeneous, competing interfacial bonds that are key to adhesion and interfacial strength. Our results show an existence of an optimum overlap length scale (∼15 nm) between polymers and cement crystals, exhibiting the best balance of strength, toughness, stiffness, and ductility for the composite. This finding, combined with the fundamental insights into the nature of interfacial bonds, provides key hypotheses for selection and processing of constituents to deliberate the best synergy in the structure and materials of platelet-matrix composites.
... Recently, the preparation of inorganic/organic nanocomposites has been reported and seems to be a more effective approach to solving the problem of agglomeration [22,23]. Because of the layered silicate structure in C-S-H, C-S-H/polymer nanocomposites are excellent candidates for the manipulation and control of properties through the intercalation of organic molecules [12,[24][25][26][27]. In fact, C-S-H stabilized by the addition of comb-like copolymers demonstrates low aggregation [28]. ...
... This result is consistent with the experimental results presented by Zhang et al. [34], in which the -COOM-groups are arranged vertically in the C-S-H layer, leading to an increase in the interlayer spacing. However, the introduction of other polymers such as polyaniline [26,35] would decrease the distance between the C-S-H layers. Fig. 9 shows the FT-IR spectra of C-S-H, PCE(obtained by evaporating the PCE solution) and CPNs. ...
... It is worth noting that the temperature range of thermal oxidation and pyrolysis of the PCE molecules is wider for the CPNs than for PCE, indicating that the PCE in the CPNs can form in two different structural locations in the C-S-H structure: grafted on the surface or partially intercalated in the interlayer regions. Using the conclusion about C-S-H/polyaniline nanocomposites made by Alizadeh et al. as a Ref. [26], the mass loss at lower temperatures is likely associated with the PCE physically adsorbed on the surface of C-S-H, which requires less energy for decomposition. Higher temperature mass loss, on the other hand, can be attributed to the presence of stronger bonds between PCE and C-S-H in the defect sites and interlayer regions. ...
... The improvement of properties of C-S-H is of significant interest as it can directly influence the performance of cement-based construction materials. Modification of the nanostructure of C-S-H by organic compounds is likely to be a promising approach to achieve this goal (Matsuyama and Young 1999a-c;Mojumdar and Raki 2006;Alizadeh et al. 2011). Several organic compounds have been previously used successfully to modify/improve the nanostructure of smectic clays (Okada et al 1990;Somwangthanaroj 2010;Natkanski 2012;LeBaron 1999). ...
Calcium-silicate-hydrate/aminobenzoic acid (C-S-H/ABA) composite systems were synthetized and characterized for the first time. Each of 3- or 4-aminobenzoic acid with a concentration of 0.01 mol. per mol. of Ca was added to the C-S-H preparations during their hydration. The C-S-H/ABA systems were filtered and dried after three weeks. These were, then, characterized by X-ray diffraction, Fourier transform infrared spectroscopy and nitrogen adsorption analysis. Porous bodies were also prepared from C-S-H/ABA compacted powders and used for the length-change and mass-change measurements in different test solutions. In addition, the microindentation technique was used to determine the creep modulus and hardness of the compacted samples. It is suggested that the C-S-H/ABA systems had improved durability and enhanced mechanical properties compared to the phase pure C-S-H reference materials. The influence of the 3- and 4-aminobenzoic acid on durability factors was similar. The C-S-H/3-ABA, however, had superior mechanical performance.
... Emeraldine can be isolated in the insulating or conducting forms, named emeraldine base and emeraldine salt (Dimitriev, 2001;Jamadade et al., 2010;Javadi et al., 1989;Lee et al., 2009;Wang, 2002), respectively (Duboriz and Pud, 2014 and Epstein, 1995), which can be identified by their characteristic bluish and greenish colors (Duboriz and Pud, 2014;. Polyaniline is frequently a good choice for manufacture of sensitive devices (Rahaman et al., 2013;Souza et al., 2008bSouza et al., , 2009Souza et al., , 2010bSouza et al., , 2011, because of its low cost, very good electrical and electronic properties and easy preparation (Alizadeh et al., 2011;Kar et al., 2011;Ram and Palaniappan, 2004;Souza et al., , 2008aSouza et al., ,c, 2010b. ...
This paper presents a new magnetic material, obtained from the modification of mango (Mangifera indica L.) fibers with polyaniline (PAni). The obtained materials were characterized through wide-angle X-ray scattering, scanning electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet-visible spectroscopy. Additionally, the electrical resistivity and magnetic behavior of the obtained samples were evaluated with the help of volume resistivity measurements assisted by probability density function analysis and magnetic force tests. The materials presented good electrical and magnetic properties. For instance, in the best case, fibers modified with PAni are approximately 120,000 times more conductive than raw mango fibers. In addition, mango fibers modified with PAni were increasingly attracted by the magnetic field, presenting magnetic force and magnetic susceptibility equal to 6.69 ± 0.05 mN/g (at 872 ± 4 Gauss) and (2.48 ± 0.04) × 10−4 m3 kg−1, respectively. As a consequence, modification of mango fibers with PAni constitutes a very promising way for the preparation of green magnetic devices.
