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Cementitious materials are the most widely used in the construction. However, cementitious materials have defects such as low tensile strength which is easy to cause the formation of cracks. In recent years, with the research and application of smart materials, intelligent cementitious materials with self-sensing, self-diagnosis and self-healing functions have received extensive researcher’s attention. In this paper, a polyacrylic hydrogel that could be utilized for self-healing of cementitious materials was designed, and the three-dimensional network structure of the hydrogel controlled the release rate of encapsulated repair agent. The phosphate-incorporated hydrogel was filled into cement slurry to prepare self-healing cementitious materials. After the cement sample cracked and water penetrated into the crack, the phosphate was released from hydrogel. Phosphate reacted with the calcium in the pore solution to form hydroxyapatite type minerals which healed the crack. The self-healing cementitious material is in a position to heal cracks of 300 μm in width. After healing for 28 days at 20oC and 95% of RH, the compressive strength of precracked specimens could reach 85% of that of intact ones.

In this study, a novel ionically crosslinked gel polymer electrolyte (PADA gel electrolyte) with a transmittance of more than 97% was successfully fabricated and applied in electrochromic devices (ECDs) as an ion transport layer. The PADA gel-based ECDs (PECDs) exhibited the large optical modulation of 61% at 660 nm, the high coloration efficiency of 78.7 cm2 C−1, and a good memory effect. The shortest colored time (tc) and bleached time (tb) of the PECD were 7.5 s and 8.5 s, respectively, due to high Li+ mobility of the PADA layer. The ionic conductivities of the PADA gel electrolyte are 1.33 × 10−2 S cm−1 and 0.56 × 10−2 S cm−1 at 25 °C and −10 °C respectively, since its conductive behavior is similar to that of liquid electrolytes. The PECDs showed good cycling durability and long-term stability, which is attributed to the stable structures of the PADA gel electrolyte.

An ionic liquid-based ionically cross-linked gel polymer electrolyte (GPE-ILs) was successfully synthesized using acrylic acid, 2-diethylaminoethyl methacrylate, methyl methacrylate, and ionic liquids. Electrochromic devices (ECDs) with an architecture of glass/FTO/WO3/GPE-ILs/FTO/glass were fabricated by a laminating technology. The devices showed performances of large optical modulation of 49.9% at 650 nm, short switching times with the coloration time (tc) of 7 s and the bleaching time (tb) of 4 s, high coloration efficiency of 96.2 cm2 C-1, and cycling stability of 200 cycles. The GPE-ILs exhibits high ionic conductivity, superior thermal stability and good self-healing ability. GPE-ILs demonstrates an ionic conductivity of 3.19 × 10-3 S cm-1 at 25 °C and the same ions migration behaviors with most widely used liquid electrolyte between −10 and 80 °C maintains more than 80% of its tensile strength after self-healing and received only 5% weight loss at 300 °C.

This paper aims to optimize high-volume limestone powder in sustainable ultra-high performance concrete (UHPC), and characterize its roles on plasticization effect, hydration kinetics, microstructure and hardened properties. The spread flow, hydration products, compressive strength, porosity and pore structure, shrinkage, embedded CO2 emission and unit cost are investigated with different substitution levels of binders by limestone powder, varying from 0 to 80 vol%. Results show that replacing high volume of binders by limestone powder is an efficient way to develop eco-friendly and low-cost UHPC. Limestone powder shows a positive mineral plasticization effect that should be considered in designing UHPC. The degree of secondary pozzolanic hydration is more intensive than C3S/C2S hydration, which can enhance the later-age strength development potential. An appropriate content of limestone powder can contribute to a higher strength, denser pore structure, diminished total free shrinkage and higher sustainability efficiency. The optimum content of limestone powder appears to be 50 vol% of the total powder content in UHPC.

A commercial PVDF Microfiltration (MF) membrane was surface modified via a simple coating method for improvement of the hydrophilicity and anti-fouling performance. Herein, trace amounts of tannin acid (TA) and Polyethyleneimine (PEI) were firstly used with (3-Chloropropyl)trimethoxysilan (CTS) to endow the PVDF membranes with hydrophilicity. The physicochemical property of the modified membranes was characterized by SEM, AFM, ATR-FTIR and XPS respectively, and a series of tests including water contact angle (WCA), underwater oil contact angle (OCA), pure water flux (PWF), anti-fouling experiments and so on were utilized to inspect the modified effect. Benefiting from the interactions among CTS, PEI and TA, several coating layers formed on the surface of the membranes and remarkable hydrophilicity with water contact angle of 16° was obtained, moreover, the pure water flux of this composite membranes could reach 10,782 L/m2·h.

A hydrophilic and anti-fouling coating layer was constructed on a polyvinylidene fluoride (PVDF) microfiltration membrane by a novel surface modification method. The pristine membrane was firstly coated by (3-chloropropyl) trimethoxysilane/polyethyleneimine and tannic acid. Then, the metal ion was induced on the coating layer to coordinate with tannic acid and polyethyleneimine, forming a more stable and hydrophilic coating on the surface. The membrane&rsquo, s surface morphology and chemical element analysis showed that the Tannic acid/ polyethyleneimine (TA/PEI) coating layer was denser and had more stability after the addition of metal ions, and this may be due to the coordination bond formed between the TA/PEI coating and metal ions. The results of the water contact angle and pure water flux measurements showed that the hydrophilicity and wettability of the modified membranes were improved obviously after introducing the metal ion layers. The anti-fouling performance and stability of the modified membrane were also characterized by the underwater oil contact angle (OCA), the separation efficiency, and the contact angle variation value for before and after the rinsing experiment. The modified membrane showed obvious stability and antifouling. Moreover, the retention rate of some composite membranes could reach 99.6%.

The storage of living cells is the major challenge for cell research and cell treatment. Here, we introduced a novel supramolecular gel cryopreservation system which was prepared in the microchannel, and the supramolecular gel (BDTC) was self-assembled by gelator Boc- O-dodecyl-l-tyrosine (BDT). This cryopreservation system could obviously minimize the cell injury because the BDTC supramolecular gel had a more compact three-dimensional network structure when the BDT gelator self-assembled in the confined space of microchannel. This compact structure could confine the growth of the ice crystal, reduce the change rate of cell volumes and osmotic shock, decrease the freezing point of the cryopreservation system, and possess better protection capability. Furthermore, the results of functionality assessments showed that the thawed cells could grow and proliferate well and remain the same growth trend of the fresh cells after the RSC96 cells flowed out from the microchannel. This novel method has potential to be used for the cryopreservation of cells, cell therapy, and tissue engineering.

Concrete is liable to form cracks owing to the limited tensile strength, which prompts researchers to propose a concept of self-healing. Inspired by the biological bones self-healing, this paper utilized hydroxyapatite as healing substances of cement-based materials and designed polyacrylamide (PAM) gel microparticles as carriers of phosphate for cement paste self-healing system. Morphology and properties of PAM gel microparticles, feasibility of hydroxyapatite as healing agents and healing efficiency were studied. The results showed that the three-dimensional crosslinked structure of PAM can encapsulate phosphate and the content of crosslinking agent can control the release rate and cumulative release of phosphate. Chloride permeability of cement paste containing PAM with phosphate is reduced after self-healing compared with plain cement paste. The healing efficiency of self-healing cement-based materials can reach 81.9% for compressive strength repair ratio and 93.2% for resistance to water penetration repair ratio after curing for 28 days. The white reaction products at the repairing section are proved to be hydroxyapatite according to multiple analytical techniques.

A novel bone-mimic self-healing cementitious material was developed by mimicking the healing process of bionic bone fracture using hydrogel impregnated with phosphate in Portland cement paste. The properties of phosphate-incorporated hydrogel, feasibility of hydroxyapatite formation in pore solution, release of phosphate from the hydrogel into cement paste, phase assemblage of self-healing products in the crack of cement paste and the self-healing efficiency were investigated with a range of analytical techniques. The phosphate-incorporated hydrogel can release phosphate into cracks at controlled rate. Carbonated and calcium deficient hydroxyapatite particles with sizes of approximately 30 μm were found as the main phase assemblage in the cracks during the self-healing process. The healing products grew from the surface of both sides to the center of crack. The compressive strength and impermeability of the self-healing cement pastes containing hydrogel impregnated with phosphates were fully restored after being cured for 28 days. The autonomous self-healing by introducing phosphate in hydrogel contributed the most to healing capacity, followed by the autogenous self-healing driven by the water released from hydrogel and the autogenous self-healing of cement paste. The hydroxyapatite-type products intermixed with minor amounts of calcite formed in the cracks accompanying the controlled release of phosphate from the hydrogel, providing the self-healing capabilities of the cement paste.

The effect of annealing on the self-organized morphology and component gradient distribution of films prepared from bimodal latexes blend containing 1:1 silicon-containing acrylate copolymer/silicon-free acrylate copolymer blend was studied using attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy with X-ray energy-dispersive (SEM-EDX) spectrometry, and atomic force microscopy (AFM). The distribution of silicon through the whole thickness of the film as a function of annealing was investigated using confocal Raman spectroscopy (CRS). AFM results show that poly(methyl methacrylate-co-n-butyl acrylate) latex fuses to form a continuous film at 25 °C. The wettability of the acrylate components and the heterogeneous composition of poly(3-[tris(trimethylsilyloxy)silyl] propyl methacrylate-co-methyl methacrylate) result in a graded block film. ATR-FTIR and SEM-EDX measurements reveal silicon-containing components segregate at the film–air interface upon annealing. CRS further shows that the nonlinear model gradient distribution of silicon is obtained, where the content of silicon component is enhanced and it gradually varies in the bulk. When the annealing temperature increases to 120 and 180 °C, blend latexes films demonstrate varying topography and phase images, indicating phase separation is induced by annealing. Furthermore, CRS implies that the destruction of the gradient structure is attributed to the phase separation of the two blend components.

An ionic complex of anionic and cationic monomers was obtained when (N,N-diethylamino)ethylmethacrylate (DEAEM) was protonated with acrylic acid (AAc). Through the free radical copolymerization of the ionic complex and acrylamide (AAm) in aqueous solution, a novel ionically crosslinked polyampholyte gel (poly(AAc-DEAEM- AAm), designated PADA) was prepared without chemical crosslinker. An investigation of swelling behavior indicated that PADA gels exhibited peculiar erosion phenomena under contact and non-contact DC electric fields. Under contact DC electric fields, PADA gels of swollen equilibrium experienced a dual response to DC fields, i.e., swelling first and then erosion. This phenomenon has not been described elsewhere. In contrast to with the contact DC electric fields, PADA gels did not undergo a swelling process, but eroded completely within 20 min under non-contact DC fields. The NaCl concentration in electrolyte solutions greatly influenced the swelling/eroding behavior of PADA gels because the ionic crosslinkages of PADA gels could be weakened and screened by salt ions. The combined effects of higher NaCI concentration and local pH change near the electrode under DC electric fields resulted in crosslinkages quickly dissociating into cationic and anionic groups. In this case, PADA gels did not experience the swelling process, but directly eroded. Moreover, the erosion rate of PADA gels was related to the voltage of the electric field. The swelling/eroding rate for the gels in contact with the cathode was faster than that for the gels in contact with the anode. This difference can be attributed to varying local pH near different electrodes.

Supramolecular hydrogel microspheres are hydrogel particles formed by the self-assembly of hydrogelators in water, through non-covalent interactions. In this paper, we provide a novel strategy to prepare supramolecular hydrogel microspheres with diameters ranging from 15 to 105 microns by using microfluidics. Since the gelation temperature is ca. 64 degrees C, the aqueous solution containing the hydrogelator was initially set at 70 degrees C so the liquid mixture can be pumped into the microfluidic device. The hydrogelator solution then pinches off into uniform micron size droplets at the narrow orifice of the microfluidic device. While traveling downstream in the microchannel, the self-assembly process occurs inside the droplets and the droplets solidify into microsphere gels when the temperature drops to ca. 64 degrees C and below. Optical and scanning electron microscopy (SEM) demonstrate that compact, entangled, round, cage-like aggregates of hydrogelator were formed within the supramolecular hydrogel microsphere, in contrast to loose and less compact aggregates within bulk hydrogel. Thermal analysis (DSC) indicates that supramolecular hydrogel microspheres are more thermally stable and can immobilize more water molecules, owing to the compact entangled three-dimensional network structures. This observation is of particular importance for potential drug delivery and biomaterials applications.