2-hydroxyethyl Acrylate Research Articles

Synthesis, characterization, thermal and fire retardant properties of new homo- and block copolymers of polyacrylate and epoxy resin with cyclotriphosphazene core

New homo- and block copolymers composed of polyacrylate and epoxy resin with hexafunctional cyclotriphosphazene core were synthesized and characterized by FT-IR and 1H-, 13C-, and 31P- NMR. The first homopolymer, PN-polyacry was prepared from the direct condensation of 2-hydroxyethyl­acrylate with acyl chloride of hexakis(4-carboxyphenoxy)cyclotriphosphazene, PN-acyl. The second homopolymer, PN-Ep, was prepared in a direct reaction of catalyzed carboxyl groups of hexakis(4-carboxyphenoxy)cyclotriphosphazene PN-COOH with epoxy resin via an oxirane ring opening re­action. The block copolymer, PN-Ep/polyacry, was prepared from the partial coupling of 2-hydroxyethyl acrylate with the PN-acyl, followed by the reaction of unreacted carboxyl groups with epoxy resin. Differential scanning calorimetry (DSC) analysis of the PN-Ep/polyacry copolymer exhibited good compatibility between polyacrylate and cured epoxy resin. Thermal gravimetric analysis (TGA) revealed that the prepared polymeric systems accumulate 30–38 wt % char at elevated temperatures, compared to neat polyacrylate and cured epoxy resin, which accumulate negligible char at 700 °C. The limiting oxygen index (LOI) exhibited significant enhancement of fire retardant properties of the prepared polymeric systems. A scanning electron microscopy (SEM) morphology study revealed that PN-polyacry and ­PN-Ep/polyacrylate produced intumescent char residues while PN-Ep produced solid dense char with a nonporous surface.

Thermoplastic Elastomer Coated-Snsb As an Anode Electrode for Li-Ion Batteries

The demand for developing next generation Li-ion batteries (LIBs) with high energy density and long cycle life drives the research toward alternative electrode materials with larger specific capacities. Among the several materials proposed to replace graphite (372 mAh g-1) as an anode material, antimony (Sb) and tin (Sn) have long been considered as an attractive replacement due to their superior lithium storage capacities of 660 mAh g−1 and 994 mAh g−1, respectively 1, 2. Unfortunately, the electrochemical performance of these materials fades during cycling because of the electrical contact loss induced by large volume variations combined with the continuous growth of a solid electrolyte interphase (SEI) layer at the surface hindering the electron transfer. The use of multi-phase active materials, such as SnSb, instead of pure metals (Sn or Sb) has been used to limit the large volume change by reacting with Li+ at different stages during the charge and discharge process 1. Unfortunately, the alloying/dealloying reaction is still accompanied by a volume change which results in the loss of electrical contact with the active material, Sn agglomeration, and the formation of SEI film on the electrode surface leading to poor electrochemical performance 3, 4. In the present work, micron-sized SnSb coated with a thin thermoplastic elastomer (TPE) is investigated as anode electrode for LIBs. The high failure strain of TPE is a very desirable feature for rechargeable LIBs as it improves the lifetime of high specific capacity anode materials that undergo mechanical fractures induced by large volume variations. Accordingly, an elastomer showing high strain property and good adhesion to the surface of the active material has been designed. Highly rubbery PS-b-PHEA was synthesized by the nitroxide meditated polymerization (NMP) method using a specific polystyrene macroinitiator allowing the presence of long hydroxyethyl acrylate blocks. Figure 1a shows the discharge capacity vs cycle number for the non-coated SnSb and the PS-b-PHEA-coated SnSb cycled at C/10 (i.e. 0.0827 A g–1). It is clearly apparent that the PS-b-PHEA-coated SnSb has superior cyclability than the non-coated SnSb with a reversible capacity of 720 mAh g–1 obtained, whereas only 356 mAh g–1 was retained after 50 cycles for the non-coated SnSb electrode. The remarkable stable capacity is attributed to the elastomer polymer film at the surface of SnSb. Indeed, highly stretchable PS-b-PHEA is able to bear the mechanical stress caused by the large volume variations and thus maintains good quality at the electrode/electrolyte interface and the inter-grains electronic percolation pathways during successive charging and discharging of the battery as well as the limiting the continuous growth of the SEI. Moreover, excellent capacity reversibility was achieved when cycled at fast kinetics (Figure 1b) and multiple C-rates (Figure 1c) confirming the strong protection role of the polymer. The advanced chemical and mechanical properties of PS-b-PHEA open up promising perspectives to significantly improve the electrochemical performance of all electrodes that are known to suffer from large volume variations. Figure 1. Discharge capacity versus the cycle number for PS-b-PHEA-coated SnSb and non-coated SnSb at a rate of (a) C/10 over 50 cycles and (b) 1C over 100 cycles, (c) cycling performance of PS-b-PHEA-coated SnSb at multiple C-rates. References M. Wachtler, J. O. Besenhard and M. Winter, J. Power Sources, 2001, 94, 189-193. P. Antitomaso, B. Fraisse, M. Sougrati, F. Morato-Lallemand, S. Biscaglia, D. Aymé-Perrot, P. Girard and L. Monconduit, J. Power Sources, 2016, 325, 346-350. A. T. Tesfaye, Y. D. Yücel, M. K. S. Barr, L. Santinacci, F. Vacandio, F. Dumur, S. Maria, L. Monconduit and T. Djenizian, Electrochimica Acta, 2017, 256, 155-161. L. Ji, M. Gu, Y. Shao, X. Li, M. H. Engelhard, B. W. Arey, W. Wang, Z. Nie, J. Xiao and C. Wang, Adv. Mater. , 2014, 26, 2901-2908. Figure 1

Yellow resistant photosensitive resin for digital light processing 3D printing

ABSTRACTDigital light processing (DLP) has been studied and developed in the field of three‐dimensional (3D) printing in recent years due to its fast curing rate and high resolution. To reduce the cost and viscosity of the resin system, the aromatic polyurethane acrylates (PUAs) were used as oligomer. The matrix resin called PUH2 consists of oligomers (PUA, bisphenol A polyoxyethylene ether dimethyl acrylate) and active diluents (hydroxyethyl acrylate, hydroxyethyl methacrylate). However, the photosensitive resin containing aromatic isocyanate groups was easily yellowed under ultraviolet light. In this article, we developed a resin for DLP 3D printing with yellowing resistance, excellent mechanical properties and high heat resistance. The optimal ratio of 3DP‐PUH2 resin was PUH2/TPO/RYOJI‐292/dye/nanosilica = 100/5/0.4/0.01/0.1, and its viscosity was 500 cp, which is suitable for DLP 3D printing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48369.

Preparation and characterization of self-crosslinking fluorinated polyacrylate latexes and their pressure sensitive adhesive applications

Self-crosslinking fluorinated polyacrylate latexes based on butyl acrylate (BA), fluorine monomer octafluoropentyl methacrylate (OFPMA), self-crosslinking functional monomers acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA) were synthesized by a monomer-starved seeded semi-continuous emulsion polymerization process. The latexes and their corresponding films were characterized by laser particle size analyser, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle goniometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results indicated that the particle size of the latexes and the gel content of the films were both independent of the amount of OFPMA employed. On the other hand, the particle size of the latexes decreased and the gel content of the films increased with the incorporation of AA and HEA as expected. Glass transition temperature (Tg) and the thermal stability of the copolymer were both improved gradually as OFPMA content increased. XPS, AFM and water contact angle measurement indicated that the fluoroalkyl groups had a tendency to enrich on the surface of the films. However, this enrichment of fluorine on the film surface was reduced after the introduction of self-crosslinking functional monomers into the system. Finally, the adhesive property of the latexes was evaluated for application as a pressure sensitive adhesive (PSA).

Color-Switchable Polar Polymeric Materials.

Spiropyran is an important mechanophore, which has rarely been incorporated as a cross-linker in polar polymer matrices, limiting its applications in innovative mechanochromic devices. Here, three spiropyrans with two- or three-attachment positions were synthesized and covalently bonded in polar poly(hydroxyethyl acrylate) (PHEA), to achieve color-switchable materials, triggered by light and when swollen in water. The negative photochromism in the dark and mechanical activation by swelling in water were investigated. Measurements of negative photochromism were conducted in solution and cross-linked PHEA bulk polymers, with both showing color reversibility when stored in the dark or on exposure to visible light. The force of swelling in water was sufficient to induce the ring-opening reaction of spiropyran. It was found that tri-substituted spiropyran (SP3) was less influenced by the polar matrix but showed the fastest color activation during swelling. SP3 also showed accelerated ring opening to the colored state during the swelling process. Bleaching rates and color switchability were investigated under swollen and dehydrated conditions. The effect of cross-link density on the swelling activation was explored to better understand the interaction between the mechanophore and the polar environment. The results demonstrated that influences from both the polar environment and the mechanochromic nature of spiropyran had an impact on the absorption intensity, rate of change, and the decoloration rate of the materials. This study provides the opportunity to manipulate the properties of spiropyrans to afford materials with a range of color-switching properties under different stimuli.

Extractable content of functional acrylic resins produced by radical copolymerization: A comparison of experiment and stochastic simulation

A comprehensive stochastic simulator that considers all probable secondary reactions essential for the description of high-temperature radical copolymerization of acrylate/methacrylate is implemented based on previously established accelerating techniques. The comparisons between the predictions and six experimental datasets are detailed for semi-batch copolymerization of 2-hydroxyethyl acrylate (HEA) with butyl methacrylate (BMA) under starved-feed condition. Macroscopic properties – free monomer and molar mass (MW) average profiles, final polymer molecular mass distributions, and the variation of acrylate composition with time– are reasonably well predicted over the range of initiator and comonomer levels studied. The simulation output also predicts the weight fraction and MW averages of the polymer chains that contain no HEA functionality, results that are compared to the experimental extractables obtained after crosslinking the copolymer resin. The general trends are well-captured, indicating that the model can be utilized in the future to optimize recipe and operating conditions to minimize the production of the non-functional material.

Reversible Hydrogel Photopatterning: Spatial and Temporal Control over Gel Mechanical Properties Using Visible Light Photoredox Catalysis.

There is a growing interest in being able to control the mechanical properties of hydrogels for applications in materials, medicine, and biology. Primarily, changes in the hydrogel's physical properties, i.e., stiffness, toughness, etc., are achieved by modulating the network cross-linking chemistry. Common cross-linking strategies rely on (i) irreversible network bond degradation and reformation in response to an external stimulus, (ii) using dynamic covalent chemistry, or (iii) isomerization of integrated functional groups (e.g., azobenzene or spiropyran). Many of these strategies are executed using ultraviolet or visible light since the incident photons serve as an external stimulus that affords spatial and temporal control over the mechanical adaptation process. Here, we describe a different type of hydrogel cross-linking strategy that uses a redox-responsive cross-linker, incorporated in poly(hydroxyethyl acrylate)-based hydrogels at three different weight percent loadings, which consists of two viologen subunits tethered by hexaethylene glycol and capped with styrene groups at each terminus. These dicationic viologen subunits (V2+) can be reduced to their monoradical cations (V•+) through a photoinduced electron transfer (PET) process using a visible light-absorbing photocatalyst (tris(bipyridine)ruthenium(II) dichloride) embedded in the hydrogel, resulting in the intramolecular stacking of viologen radical cations, through radical-radical pairing interactions, while losing two positive charges and the corresponding counteranions from the hydrogel. It is shown how this concerted process ultimately leads to collapse of the hydrogel network and significantly (p < 0.05) increases (by nearly a factor of 2) the soft material's stiffness, tensile strength, and percent elongation at break, all of which is easily reversed via oxidation of the viologen subunits and swelling in water. Application of this reversible PET process was demonstrated by photopatterning the same hydrogel multiple times, where the pattern was "erased" each time by turning off the blue light (∼450 nm) source and allowing for oxidation and reswelling in between patterning steps. The areas of the hydrogel that were masked exhibited lower (by 1-2 kPa) shear storage moduli (G') than the areas that were irradiated for 1.5 h. Moreover, because the viologen subunits in the functional cross-linker are electrochromic, it is possible to visualize the regions of the hydrogel that undergo changes in mechanical properties. This visualization process was illustrated by photopatterning a larger hydrogel (∼9.5 cm on its longest side) with a photomask in the design of an array of stars.

Correlations between odour activity and the structural modifications of acrylates

Acrylates (acrylic esters) are versatile monomers that are widely used in polymer formulations because of their highly reactive α,β-unsaturated carboxyl structure. Commonly used acrylates such as butyl acrylate are known to emit a strong unpleasant odour, and the monomers are therefore potential off-odorants in acrylic polymers. However, up to now, the odour properties of structurally related acrylic esters have not been characterised in detail. To obtain deeper insights into the smell properties of different acrylates, we investigated the relationship between the molecular structure and odour thresholds as well as the odour qualities of 20 acrylic esters, nine of these synthesised here for the first time. The OT values of 16 acrylates fell within the range from 0.73 to 20ng/Lair, corresponding to a high-odour activity. Moreover, sec-butyl acrylate and 2-methoxyphenyl acrylate showed even lower OT values of 0.073 and 0.068, respectively. On the other hand, the OT values of the hydroxylated acrylates 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate were 5-244 times higher than those of the other compounds, demonstrating that the presence of a hydroxyl group obviously favours odour inactivity.

Kinetic Model and Synthesis of Hyperbranched Polyurethane Acrylates from Monomers A2 and B3 with End-Capping Molecules BR

The preparation of hyperbranched polymers by the polymerization of monomers A2 and B3 with monofunctional monomers BR was investigated by recursive and kinetic models. A diagram of the gel and sol regions corresponding to the composition of the monomers was proposed. According to the kinetic model, the average degree of polymerization and the degree of branching (DB) that are dependent on the conversion and initial compositions of the reactants were calculated by a generating function method. If the molar ratio of B3/A2/BR was 1:3:3, then polymers with a weight-average degree of polymerization of 171 and a DB of 0.97 could be obtained at a conversion of 0.99. Polyurethane acrylates were further prepared from various mixtures of trimethylolpropane ethoxylate (B3), hexamethylene diisocyanate (A2), and hydroxyethyl acrylate (BR). The molecular weights of the polymers predicted by the model were in good agreement with those determined by gel permeation chromatography.

A temperature‐responsive polyurethane and its biocompatible and biodegradable nanohydrogels with uniform cross‐linking networks

We prepared a temperature‐responsive polyurethane (PU) with a coil‐to‐globule transition temperature of 36°C in aqueous media, by using polyethylene glycol‐4,000 (PEG‐4000), polycaprolactone diol‐1,000 (PCL‐1000), diphenylmethane diisocyanate‐50, and hydroxyethyl acrylate. Nanohydrogels were synthesized from temperature‐responsive PU through precipitation polymerization without employing a crosslinker. Due to the unique molecular structure of temperature‐responsive PU, PU nanohydrogels have uniform cross‐linking networks resulting in narrow volume phase transition temperature range, showing sensitive temperature responsiveness. Additionally, PEG and PCL segments provide PU nanohydrogels excellent biocompatibility and biodegradability, respectively. POLYM. ENG. SCI., 59:1517–1523 2019. © 2019 Society of Plastics Engineers

Thermally Healable Polyurethanes Based on Furfural-Derived Monomers via Baylis-Hillman Reaction

Two novel acrylate monomers with diol group, 2-hydroxyethyl 2-(furan-2-yl(hydroxy)methyl)acrylate and methyl 2-(hydroxy(5-(hydroxymethyl)furan-2-yl)methyl)acrylate, were synthesized via Baylis-Hillman reaction in moderate yields. The monomer 2-hydroxyethyl 2-(furan-2-yl(hydroxy)methyl)acrylate was obtained from furfural and 2-hydroxyethyl acrylate (HEA); methyl 2-(hydroxy[5-(hydroxymethyl)furan-2-yl)methyl)acrylate was prepared from 5-hydroxymethl furfural (HMF) and methyl acrylate. The monomer 2-hydroxyethyl 2-(furan-2-yl(hydroxy)methyl)acrylate reacted with toluene diisocyanate (TDI)-derived or hexamethylene diisocyanate (HDI)-derived diisocyanate oligomers to obtain the corresponding linear polyurethane oligmers PU-1T and PU-1H. Similarly, the diol methyl 2-(hydroxy(5-(hydroxymethyl)furan-2-yl)methyl)acrylate reacted with TDI- or HDI-derived diisocyanate oligomers to obtain the corresponding linear polyurethane oligmers PU-2T and PU-2H. The number-average molecular weights of the linear polyurethane oligomers are approximately 300–350 Da. There are furan groups in the linear polyurethane oligomers PU-1T, PU-1H, PU-2T and PU-2H, which makes them capable of undergoing reversible Diels-Alder reaction with 4,4′-bismaleimidodiphenylmethane (BMI) to form the corresponding crosslinked polyurethanes CPU-1T, CPU-1H, CPU-2T and CPU-2H. Pencil hardness of CPU-1T, CPU-1H, CPU-2T and CPU-2H are 3H, 2H, 2H and HB, respectively. Glass transition temperatures of CPU-1T, CPU-1H, CPU-2T and CPU-2H are 104.8, 97.6, 5.1 and 1.2 °C, respectively. TGA analysis shows that Td90 values of the CPUs range from 180 to 250 °C. Furthermore, the reversible crosslinked polyurethanes CPU-1T and CPU-1H can be completely self-healed at 90 °C for 3 h, while CPU-2T and CPU-2H can self-heal at 80 °C for 3 h presumably due to their low glass transition temperatures.

Synthesis and Properties of Tung Oil-Based Unsaturated Co-Ester Resins Bearing Steric Hindrance.

New tung oil (TO)-based, unsaturated, co-ester (Co-UE) macromonomers bearing steric hindrance were synthesized by modifying a TO-based maleate (TOPERMA) monomer with an anhydride structure with hydroxyethyl methacrylate (HEMA) and methallyl alcohol (MAA), respectively. The obtained Co-UE monomers (TOPERMA-HEMA and TOPERMA-MAA) were then characterized by 1H NMR and gel permeation chromatography (GPC). For comparison, hydroxyethyl acrylate (HEA)-modified TOPERMA (TOPERMA-HEA) was also synthesized and characterized. Subsequently, the obtained Co-UEs were thermally cured with styrene, and the ultimate properties of the resulting materials were studied. It was found that by introducing the structure of steric hindrance into the TO-based Co-UE monomer, the tensile strength and Young’s modulus of the resulting materials were improved. Furthermore, by reducing the length of the flexible chain in the Co-UE monomer, the tensile strength, Young’s modulus, and glass transition temperature (Tg) of the resultant materials were also improved. The TOPERMA-MAA resin gave the best performance in these TO-based Co-UE resins, which showed a tensile strength of 32.2 MPa, Young’s modulus of 2.38 GPa, and Tg of 130.3 °C. The developed ecofriendly materials show promise in structural plastic applications.

Tough, structurally colored fabrics produced by photopolymerization

Structural coloration from photonic crystals (PCs) has attracted great interests owing to the chemical colorants-free process and highly brilliant color effects. However, the poor durability of the structural color severely restrains its practical applications. Based on this, a photopolymerization process to form polymer network structure was tactfully introduced in fabricating tough PCs on fabric substrates. The differences of surface morphology, tensile strength, binding strength and structural colors between poly(styrene-methacrylate) (P(St-MAA)) PCs and resultant P(St-MAA) PCs (named PHEA@P(St-MAA) PCs) were detailedly investigated and characterized. The results show that poly(hydroxyethyl acrylate) (PHEA) film is formed by photocross-linking reaction with diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide as initiator on the surface and interstices of P(St-MAA) PCs, which effectively improves the tensile strength and binding strength of P(St-MAA) PCs on fabric substrates. The PHEA@P(St-MAA) PCs display brilliant structural colors and obvious iridescence as well, although become red-shifted in accordance with Bragg’s law. It is concluded that this research will offer theoretical basis and practical guidance for the fabrication of the tough photonic crystals on fabric substrates.

Recommendation to include hydroxyethyl (meth)acrylate in the British baseline patch test series.

(Meth)acrylates are potent sensitizers and a common cause of allergic contact dermatitis (ACD). The frequency of (meth)acrylate ACD has increased with soaring demand for acrylic nails. A preliminary audit has suggested a significant rate of positive patch tests to (meth)acrylates using aimed testing in patients providing a clear history of exposure. To date, (meth)acrylates have not been routinely tested in the baseline patch test series in the U.K. and Europe. To determine whether inclusion of 2-hydroxyethyl methacrylate (2-HEMA) 2% in petrolatum (pet.) in the baseline series detects cases of treatable (meth)acrylate ACD. During 2016-2017, 15 U.K. dermatology centres included 2-HEMA in the extended baseline patch test series. Patients with a history of (meth)acrylate exposure, or who tested positive to 2-HEMA, were selectively tested with a short series of eight (meth)acrylate allergens. In total 5920 patients were consecutively patch tested with the baseline series, of whom 669 were also tested with the (meth)acrylate series. Overall, 102 of 5920 (1·7%) tested positive to 2-HEMA and 140 (2·4%) to at least one (meth)acrylate. Had 2-HEMA been excluded from the baseline series, (meth)acrylate allergy would have been missed in 36 of 5920 (0·6% of all patients). The top (meth)acrylates eliciting a positive reaction were 2-HEMA (n = 102, 1·7%), 2-hydroxypropyl methacrylate (n = 61, 1·0%) and 2-hydroxyethyl acrylate (n = 57, 1·0%). We recommend that 2-HEMA 2% pet. be added to the British baseline patch test series. We also suggest a standardized short (meth)acrylate series, which is likely to detect most cases of (meth)acrylate allergy.

Extrudable hydroxyapatite/plant oil-based biopolymer nanocomposites for biomedical applications: Mechanical testing and modeling

Towards developing bone-inspired, high performance composite biomaterials, two nanocomposite inks, consisting of a plant oil-based biopolymer resin (soybean oil epoxidized acrylate (SOEA)) and silanized nano-hydroxyapatite (Si-nHA) particles with and without diluent hydroxyethyl acrylate (HEA), were extruded using direct ink writing to fabricate filaments of differing volume fractions. HEA was hypothesized to lower ink viscosity, improve Si-nHA dispersion and extrudability, and therefore result in better relative improvements in mechanical properties over those of the base resin. Thermogravimetric analysis, scanning electron microscopy and uniaxial tensile tests were conducted. Strength, toughness, and stiffness of both resins were improved by the addition of Si-nHA. The HEA improved dispersion and extrudability. This resulted in better particle alignment and relatively greater augmentation of mechanical properties. The experimental data for both biopolymer resins were used to calibrate 3D representative volume element (RVE) finite element micromechanical models, while the experimental data for the nanocomposite filaments were employed to validate these models. The Young's moduli from the computational models were also compared with experimental data and with analytical predictions calculated using the Mori-Tanaka method. The predictions of 3D RVE models correlated well with the experimental data while, for higher volume fractions, the Mori-Tanaka results diverged, similar to previous reports.

Development, characterization, swelling, and network parameters of amino acid grafted guar gum based pH responsive polymeric hydrogels

This study includes the synthesis of graft copolymer (GG-g-PAPA) from N-Acryloyl-L-phenylalanine (APA) and guar gum through free radical polymerization. Then, the novel pH sensitive GG-g-PAPA-cl-(PHEA-co-PAMPS) [GGAH] polymeric hydrogels were synthesized by employing free radical cross-linking polymerization using graft copolymer, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and 2-hydroxy ethyl acrylate (HEA). The GGAH hydrogels were characterized using FTIR and SEM. Swelling studies of GGAH hydrogels were performed in distilled water, pH 1.2, and pH 7.4 solutions. The network and swelling kinetic parameters of GGAH hydrogels are also calculated.

Room-temperature fabrication of TiO2-PHEA nanocomposite coating with high transmittance and durable superhydrophilicity

Coatings with high transmittance and superhydrophilicity play an outstanding role in many practical applications such as antifogging, antifouling, self-cleaning, etc. The durability greatly affects their applications. In the current work, TiO2 organic nanocomposite coating with high transmittance and durable superhydrophilicity was prepared via the homogeneous compositing of modified anatase TiO2 nanoparticles (NPs) and hydroxyethyl acrylate (HEA) without any solvent. The curing process of coating and the formation of nanometer rough structure were carried out simultaneously under ultraviolet (UV) irradiation at room temperature. The composite coating exhibited an excellent intrinsic superhydrophilicity (water contact angle less than 3° in 0.45 s), high transmittance (above 90% in the visible wavelength), mechanical robustness, photocatalytic activity, anti-fogging and anti-fouling properties. The superhydrophilicity of the as-prepared nanocomposite coating could last for 330 days in the laboratory environment, which was quite a long time for maintaining the superhydrophilicity of TiO2 coatings in the literature reports. The durable superhydrophilicity is attributed to the enhancement of intrinsic hydrophilicity and the increase of surface roughness. The superhydrophilic TiO2-PHEA nanocomposite coating has a wide application prospect in solar cells, building and automobile antifogging glass, antifogging lens and other fields. The methodology proposed in this work can be applied to the fabrication of new superhydrophilic TiO2-polymeric composite materials using a low-cost, efficient and simple methodology.

Effects of monomer functionality on physical properties of 2-ethylhexyl acrylate based stretchable pressure sensitive adhesives

Recently, the interest in flexible displays has been increasing due to the demand for wearable and flexible electronics which can be curved, bent and/or stretched without impinging their performance. Most importantly, the development of stretchable adhesives is indispensable in order to adhere the components of the stretchable display without defects or flaws at interfaces during operation. In this study, UV curable pressure sensitive adhesives (PSAs) composed of acrylic monomers were successfully characterized in terms of physical properties for the stretchable display application. With the base monomer of 2-ethylhexyl acrylate, various acrylic monomers exhibited different properties, especially instantaneous strain reversibility was achieved using methyl acrylate (MA) and 2-hydroxyethyl acrylate (HEA). Interestingly the MA incorporated PSA became more elastic as strain increased from 15% to 30%, reducing hysteresis loss close to zero. Acrylic acid (AA) containing PSA showed significantly higher peel adhesion compared to the other monomers. Rheological studies are also performed to support the aspect of the peel adhesion values which correspond to the trend of loss modulus (G”). Transmittance of each synthesized PSA was sufficiently clear (>95%) demonstrating the feasibility of synthesized UV curable PSAs for optically clear adhesives.

Fabrication and characterisation of curcumin loaded pH dependent sodium alginate-g-poly(acryloyl phenylalanine)-cl-ethylene glycol vinyl ether-co- hydroxyethyl acrylate hydrogels and their in-vitro, in-vivo and toxicological evaluation studies

pH responsive interpenetrating polymeric network hydrogels (IPN-hydrogels) composed of sodium alginate-g-poly(N-acryloyl-l-phenylalanine) (NaAlg-g-PAPA), ethylene glycol vinyl ether (EGVE) and, hydroxyethyl acrylate (HEA) were designed through a free radical polymerization reaction. A hydrophobic drug curcumin (phytopolyphenol) successfully loaded into these hydrogels by in-situ method. The formation of NaAlg-g-PAPA-cl-(PEGVE-co-HEA) [SAEH] hydrogels, its chemical interaction with the curcumin and surface morphology were investigated by the FTIR, XRD, TGA, DSC and SEM techniques. The maximum percentage encapsulation efficiency of curcumin (CUR) in sodium alginate hydrogel (SAEH) has found as 75%. The in-vitro drug delivery profile was studied both in pH 1.2 (stimulated gastric fluid) and pH 7.4 (intestinal condition) dissolution mediums at 37 °C. Antiproliferative activity In-vitro studies were conducted against the MCF-7 and HepG2 cancer cells. It is revealed that significant superior action of curcumin loaded formulation on cancer cell death compared to free curcumin. In addition, In-vivo studies were conducted for CUR-SAEH hydrogels against CUR by taking Wistar rat (male and female) as animal model. Toxicological evaluation studies of curcumin loaded sodium alginate based hydrogels were carried out to see the effect of formulated hydrogels on organs of animals. These results revealed that there is no any significant toxicity is observed in organs of animal and suitable for the oral administration.

Superior Electrochemical Performance of Thin-Film Thermoplastic Elastomer-Coated SnSb as an Anode for Li-ion Batteries

The high failure strain of thermoplastic elastomers (TPEs) is a very desirable feature for rechargeable Li-ion batteries by improving the lifetime of high specific capacity anode materials that undergo mechanical fractures induced by large volume variations. In this work, poly(styrene-b-2-hydroxyethyl acrylate) called PS-b-PHEA was synthesized by a nitroxide meditated polymerization method. Owing to the use of a specific polystyrene macroinitiator (SG1), a suitable TPE copolymer with long hydroxyethyl acrylate blocks to ensure good mechanical properties is obtained for the first time. We show that the electrochemical properties of the PS-b-PHEA-coated SnSb anode are drastically improved by suppressing the crack formation at the surface of the electrode. Indeed, electrochemical characterization revealed that a high and stable gravimetric capacity over 100 cycles could be achieved. Moreover, excellent capacity reversibility was achieved when cycled at multiple C-rates and fast kinetics confirming the strong protection role of the polymer. The advanced chemical and mechanical properties of PS-b-PHEA open up promising perspectives to significantly improve the electrochemical performance of all electrodes that are known to suffer from large volume variations.