Acrylate Liquid Research Articles

Ultra-low temperature-responsive liquid crystal elastomers with tunable drive temperature range

Liquid crystal elastomers (LCEs) have recently gained significant attention in the field of smart materials due to their ability to respond to external stimuli, offering substantial potential for practical applications in soft robotics and bioengineering where actuation and sensing are crucial. However, conventional LCEs typically have high driving thresholds, significantly limiting their practical utility. Thus, reducing the driving temperature of LCEs remains a critical challenge in current research. In contrast to complex chemical molecular modifications aimed at lowering the driving threshold, our work employs a straightforward one-step cross-linking method to synthesize bisacrylate LCEs with varying compositions. These LCEs exhibit remarkably low driving temperatures and improved actuation performance. The monofunctional and difunctional acrylate liquid crystal mixtures employed in our experiments possess different ranges of anisotropy and can be effectively incorporated into the liquid crystal elastomers. Following polymerization, these LCEs demonstrate actuation capabilities at temperatures as low as −18 °C while maintaining excellent performance even at elevated temperatures of up to 60 °C. Moreover, in a series of 50 repeat experiments, the LCEs exhibited exceptional repeatability with a minimal error rate of 2.0 %. Additionally, the introduction of carbon nanotubes into the LCEs resulted in achieving a significant angular deflection of up to 100° within a narrow range of low light intensities, specifically between 26.19 mW cm−2 and 32.38 mW cm−2, highlighting the continued effectiveness of these materials even with this modification.

Carbene-Based Bioadhesive Blended with Amine, Thiol, and Acrylate Liquid Additives

Light-activated carbenes provide a unique method of non-specific covalent bond formation needed in bioadhesives and rapid gelation. The highly reactive carbenes formed upon UV irradiation allow for binding to a wide range of natural and synthetic substrates in addition to cohesive bonds. However, little is known about how these crosslinkers would behave in the presence of additives, which are important for tuning material properties. This work investigates carbene-based bioadhesives in the presence of various liquid additives containing reactive functional groups of hydroxyl, thiol, amine, or acrylate. Steady shear viscosity, dynamic mechanical properties, microstructure, and reactive functional groups are evaluated by photorheometry, scanning electron microscopy, and FTIR spectroscopy. The triol hydroxy additive maintains the storage modulus despite dilution of the diazirine crosslinker. The thiol additive reduces apparent viscosity while maintaining material properties. Polyamine accelerates ester hydrolysis and increases hydrophilicity. For the first time, diacrylate polymerization is demonstrated by photoactivated diazirine, the carbene precursor. The diacrylate additive displays synergistic enhancement of the dynamic modulus within the binary composite, reaching 977 kPa compared to 82 kPa of neat carbene-based bioadhesive. The polymerization of acrylates initiated by diazirine photolysis opens possibilities for acrylate initiation and hybrid composite biomaterials.

Toward In Silico Design of Highly Tunable Liquid Crystal Elastomers

In this work, a two-component acrylate liquid crystal elastomer, with varying composition and templating phase, is synthesized in the laboratory and investigated in parallel using atomistic molecular dynamics simulations. The anisotropic nature of both the mono- and bifunctional acrylates used in this study enables a large tunability in the compositional range while still retaining liquid crystalline properties in the final elastomer. The use of simulations allows important evaluation and comparison of physical properties such as glass transition temperature, nematic to isotropic phase transition temperature, and order parameter. The dependence of physical properties (glass transition, nematic to isotropic transition, order parameter, coefficient of thermal expansion, and mechanical properties) is established as a function of chemical composition, showing a high degree of tunability. Interestingly, the templating phase (nematic or isotropic) is also shown to impact the subsequent elastomer properties, with excellent agreement shown here between experiments and simulations. The in silico approach to polymerization, coupled with excellent comparison with the experimental system, represents a new methodology for the targeted design of liquid crystal elastomers with specific physical properties.

Mesomorphic behaviors of some acrylate liquid crystals and their application for polarizer preparation

ABSTRACT Two series of acrylate liquid crystals with enantiotropic SmA and SmC phases were synthesised. With increasing the alkoxy chain length, SmC phase was favourable to be formed. The mesophases were confirmed by taking small angle X-ray scattering patterns. Moreover, a diacrylate liquid crystal with an enantiotropic SmA phase was synthesised. Smectic liquid crystal mixtures were prepared using the diacrylate liquid crystal (or a mixture of an acrylate liquid crystal and the diacrylate one) and a dichroic dye. After photopolymerisation at the SmA phase, polymeric polarisers were obtained. The degree of polarisation was increased with increasing the dye concentration and film thickness.

Triple-Shape-Memory Soft Actuators from an Interpenetrating Network of Hybrid Liquid Crystals.

In this work, the formation of triple-shape-memory liquid crystalline-interpenetrating polymer network (LC-IPN) actuators based on a hybrid acrylate-oxetane LC mixture is reported. Orthogonal polymerization of the oxetane and acrylate liquid crystals creates polymer films with two distinct glass-transition temperatures. The use of these two transitions for one-way triple-shape-memory actuation and two-way bending actuation with a broad temperature window for actuation is demonstrated. Our results combine shape memory polymers with liquid crystal-based soft actuators having advanced stimuli-responsive properties.

Study on the morphologies and electro-optical properties of cyano-phenyl-ester liquid crystals/polymer composite films prepared by a stepwise polymerisation

ABSTRACT In this work, a series of liquid crystal molecules containing cyano-phenyl-ester was designed and synthesised. Subsequently, a novel cyano-phenyl-ester liquid crystals (CPE-LCs) with a wide temperature range from −30°C to 96.4°C were developed by mixturing these liquid crystal compositions. Then as the host materials, the CPE-LCs were used for preparing polymer-dispersed and polymer-stabilised cholesteric liquid crystals (PD&SCLC) composite films by a stepwise polymerisation. The morphologies and electro-optical properties of the as-made composite films were systematically investigated through varying the acrylate liquid crystalline polymerisable monomers content, chiral doping R1011 content, applied electric field intensity and polymerisation time. Indeed, the formation of homeotropically aligned anisotropic polymer networks (HAAPNs) enabled to reduce the driving voltage of PD&SCLC from 86.6 V to 22.2 V with a reasonable contrast ratio. This work provides a new method to optimise PD&SCLC composite films in terms of the host liquid crystals.

The Effect of Gold Nanoparticles on the Switching Properties of Acrylate Liquid Crystal Polymer

The Effect of Gold Nanoparticles on the Switching Properties of Acrylate Liquid Crystal Polymer

Fabrication of Porous Al2O3 Film by Freeze Tape Casting

Porous thick film of alumina which is fabricated by freeze tape casting using a camphene-camphor-acrylate vehicle. Alumina slurry is mixed above the melting point of the camphene-camphor solvent. Upon cooling, the camphene-camphor crystallizes from the solution as particle-free dendrites, with the powder and acrylate liquid in the interdendritic spaces. Subsequently, the acrylate liquid is solidified by photopolymerization to offer mechanical properties for handling. The microstructure of the porous alumina film is characterized for systems with different cooling rate around the melting temperature of camphor-camphene. The structure of the dendritic porosity is compared as a function of ratio of camphene-camphor solvent and acrylate content, and powder volume fraction in acrylate in terms of the dendrite arm width.

Synthesis and characterisation of star-shaped liquid crystalline polymer with a POSS core

The star-shaped POSS-graft-LCP with POSS as the core and liquid crystal polymer, poly{6-(4ʹ-octyloxyphenyl-4″-benzoyl)hexyl acrylate}, as arms was prepared by atom transfer radical polymerisation technique using octa(3-chloropropyl) polyhedral oligomeric silsesquioxane [POSS-(CH2CH2CH2Cl)8] as initiator. For comparison, the linear liquid crystal polymer, poly{6-(4ʹ-octyloxyphenyl-4″-benzoyl)hexyl acrylate} (LLCP), was obtained by conventional radical polymerisation. Both liquid crystal polymers were characterised by FT-IR, 1H NMR, 13C NMR, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, polarised optical microscopy and X-ray diffraction analysis. The liquid crystal phase behaviour research demonstrated that both liquid crystal polymers were reversible thermotropic nematic liquid crystal materials. The number of polymerisation degree of every arm attached on POSS in POSS-graft-LCP impacted greatly on the liquid crystal properties and only a small one was necessary for it to exhibit a broad liquid crystal range. Results further demonstrated that the special star-shaped topology of POSS and the eight arms attached helped POSS-graft-LCP form and stabilise liquid crystal phase easily. This research may further expand the way to star-shaped LCPs by employing a variety of (meth)acrylate and other vinyl liquid crystalline monomers.

Liquid crystalline textures and polymer morphologies resulting from electropolymerisation in liquid crystal phases

A small fraction of an acrylate liquid crystalline monomer (≤5%) is mixed into nematic and smectic liquid crystalline phases, and polymerised through the application of a voltage (electropolymerisation).

Studying collapse potential of gypseous soil treated by grouting

Gypseous soil is a collapsible soil, which causes large deformations in the buildings which are constructed on it. Therefore, several methods have been used to minimize this effect, such as replacing the gypseous soil or stabilizing it (grouting or soil improvement).This study presents the results of tests carried out on four types of gypseous soil with different properties and various gypsum contents. The testing was conducted on undisturbed samples to evaluate the compressibility of the gypseous soil under different conditions. The samples were grouted with acrylate liquid. The treated samples showed that the acrylate liquid was able to reduce the compressibility of the gypseous soil by more than 60–70%. This is attributed to the acrylate liquid film coating the gypsum particles, and thus, isolating them from being subjected to the effect of water. The treated gypseous samples exhibited a low collapse potential in which the acrylate liquid reduced the collapsibility of the gypseous soil by more than 50–60%. The acrylate liquid affected the shear strength parameters of the gypseous soil by increasing the cohesion and decreasing the angle of internal friction.For unsoaked samples, it was observed that the cohesion increased and the angle of internal friction relatively decreased. This behaviour may be attributed to the cohesion effect, caused by the presence of the acrylate liquid, and because contact between particles was prevented which caused a reduction in friction. As long as the specimens were saturated, the strength of the sand appeared to increase at the same rate as for an increase in total stress. Once the sand became unsaturated, the rate of increase in strength decreased, and in fact, the strength decreased when the suction was increased beyond some limiting value.

Wetting and drying collapse behaviour of collapsible gypseous soils treated by grouting

Gypseous soil is a collapsible soil which causes large deformations in buildings which are constructed on it; therefore, several methods were used to minimize this effect, like replacing the gypseous soil or by soil stabilization (groutingorsoilimprovement).Thisstudypresentstestresults carried out on four types of gypseous soils which have differ- ent properties and with various gypsum contents. Testing was carried out on undisturbed samples to evaluate the compress- ibility of gypseous soil under different conditions. The sam- ples were grouted with acrylate liquid. The treated samples showed that the acrylate liquid reduces the compressibility of the gypseous soil by more than 60-70 %. This is attributed to the acrylate liquid film coating the gypsum particles and so isolating them from being subjected to the effect of water. The treated gypseous samples exhibited a low collapse potential, where the acrylate liquid reduced the collapsibility of the gypseous soil by more than 50-60 %. The acrylate liquid affects the shear strength parameters of the gypseous soil by increasing the cohesion and decreasing the angle of internal friction. For the untreated soil, most compression takes place during the first cycle of loading, and then the rate of the deformation increment decreases slightly to become nearly constant at the later two cycles. For a 6-h soaking period, 15- 60 % of the settlement ratio of untreated soils occurred during the first minute, whilst for the treated soils only 2-15 % occurred during the first minute. Most compression occurs during the first cycle of loading, and then the rate of deforma- tion decreases slightly to become nearly constant at the other two cycles. Fora 6-hsoaking period, 9-44% ofthe settlement ratio of untreated soils occurred during the first minute, whilst for the treated soils only 1.5-11 % occurred during the first minute. The compression in a drying-wetting con- dition was less than that of the compression in wetting repeated test by 20 %.

Treatment of collapse of gypseous soils by grouting

Gypseous soil is a collapsible soil, which causes large deformations in buildings that are constructed on it. Various methods have been used to minimise this effect, such as replacing the gypseous soil or using soil stabilisation (grouting or soil improvement). This study was carried out on four types of gypseous soils that have different properties and various gypsum contents. The testing was carried out on remoulded samples to evaluate the compressibility of gypseous soil under different conditions. The samples were grouted with acrylate liquid. The relationships between the injection pressure and the radius of flow, between time of injection and radius of flow, and between time and quantity of acrylate liquid are investigated on four soils. The treated samples showed that the acrylate liquid reduces the compressibility of the gypseous soil by more than 60–70%. This is attributed to the acrylate liquid film coating the gypsum particles and so isolating them from being subjected to the effect of water. The treated gypseous samples exhibited a low collapse potential, where acrylate liquid reduced the collapsibility of the gypseous soil by more than 50–60%. The acrylate liquid affects the shear strength parameters of the gypseous soil by increasing the cohesion and decreasing the angle of internal friction.

Synthesis of a liquid-crystalline resin monomer with the property of low shrinkage polymerization

To reduce the polymerization shrinkage of the dental resin composites, a new liquid-crystalline resin monomer was developed. The acrylate liquid crystalline resin monomer (ALCRM), (4-3-(acryloyloxy)-2-hydroxypropoxy) phenyl 4-(3-(acryloyloxy)-2-hydroxypropoxy) benzoate, was synthesized by a three-step method. Using the ALCRM as the main monomer, the degree of conversion (DC) and the volume shrinkage of the resin matrix were compared with the traditional composite resin monomer (Bis-GMA), 2,2-bis[4-(2-hydroxy-3-methacryloyloxy-propoxy)-phenyl] propane. The new monomer showed liquid crystalline characteristics with a mesomorphic phasetransition temperature between 18ºC and 42ºC. When copolymerized with triethylene glycol dimethacrylate (TEGDMA) at a weight ratio of 7:3, the DC of ALCRM was higher and the volume shrinkage was 3.62±0.26%, which was less than that of the Bis-GMA. The ALCRM exhibits promising potential for the development of superior dental resins with low volume shrinkage.

Investigation of the mechanical properties of a low-shrinkage liquid crystalline matrix combined with nano-hydroxyapatite

The objective of this study was to investigate the mechanical properties of a low-shrinkage acrylate liquid crystalline resin matrix (ALCRM), (4-3-(acryloyloxy)-2-hydroxypropoxy) phenyl 4-(3-(acryloyloxy)-2-hydroxypropoxy) benzoate, combined with nano-hydroxyapatite (na-HA). The ALCRM monomer and diluent monomer triethylene glycol dimethacrylate (TEGDMA) were mixed at a mass ratio of 7:3 to prepare the resin matrix. The volume shrinkage of the ALCRM/TEGDMA and the traditional resin matrix Bis-GMA (2, 2-bis [4-(3-methacryloxy-2-hydroxypropoxy) phenyl] propane)/TEGDMA were measured. Then 20%, 30%, and 40% na-HA were added to ALCRM/TEGDMA and Bis-GMA/TEGDMA, respectively. Compressive strength (CS) and Vickers hardness (VHN) were tested to identify mechanical properties of the composites. The volume shrinkage of the ALCRM/TEGDMA was 3.60% ± 0.36%, which was lower than that of the traditional resin matrix. Moreover, with the same amount of na-HA filler, the mechanical properties of the ALCRM-based composites were superior to those of Bis-GMA-based composites. ALCRM-based composites exhibited the highest CS and VHN values when the filler content was 30%. These results indicate that the low-shrinkage liquid crystalline resin matrix has strong mechanical properties after incorporating the na-HA. The experimental ALCRM-based composites have promising potential for the development of novel low-shrinkage dental resins with strong mechanical properties.

Synergic Effect of Acrylate Liquid Rubber and Bisphenol A on Toughness of Epoxy Resins

The synergic effect of acrylate liquid rubber with pendant epoxy group and bisphenol A on the toughness of epoxy resins was presented in this paper. The addition of bisphenol A enhances the impact strength and elongation at break of epoxy resin and actually increases the ductibility of epoxy resin matrix. Much higher toughness efficiency can be achieved for the ALR modified epoxy resins by the incorporation of bisphenol A at the same time. The synergic promotion effect of acrylate liquid rubber and bisphenol A on the toughness efficiency of epoxy resins is attributed to the two-phase morphology and high ductibility of matrix, and the resultant large stress white zones and high shear yielding during the fracture process.

Study on modification of epoxy resins with acrylate liquid rubber containing pendant epoxy groups

Study on modification of epoxy resins with acrylate liquid rubber containing pendant epoxy groups

Network polymers with cholesteric liquid crystalline order prepared from poly(γ-butyl L-glutamate)-butyl acrylate liquid crystalline system

Polymer composites consisting of poly(γ-butyl L-glutamate) (PBuLG) and crosslinked poly(butyl acrylate) (PBuA) have been prepared by causing butyl acrylate (BuA) to polymerize in PBuLG-BuA cholesteric liquid crystalline states. The composites exhibited cholesteric organizations in bulk and in swollen states. Microscopic as well as macroscopic swelling behaviour of the composites was examined and was discussed in relation to their crosslink densities. About two-thirds of the PBuLG component could be eliminated from the composites by extraction with either chloroform or dichloroacetic acid (DCA), and the extracted composites still possessed cholesteric organizations. Practically complete removal of the PBuLG component from the composites was achieved by hydrolytic extraction with a DCA-HCl mixture. The PBuA polymer networks thus obtained exhibited no cholesteric organization, but once again the cholesteric organizations emerged when the networks were swollen in solvents. This observation was interpreted in terms of the topology of the networks constructed in cholesteric liquid crystalline states.

Immobilization of cholesteric structure in poly(γ‐butyl L‐glutamate)‐butyl acrylate liquid crystalline system

Immobilization of cholesteric structure in poly(γ‐butyl L‐glutamate)‐butyl acrylate liquid crystalline system

Topological Polymer Networks Retaining Cholesteric Liquid Crystalline Order Without Mesogen

Abstract Crosslinked poly (butyl acrylate) which possesses cholesteric liquid crystalline order has been prepared. First, butyl acrylate was caused to polymerize in a poly(γ-butyl L-glutamate)—butyl acrylate liquid crystalline state. Then, the poly(γ-butyl L-glutamate) component was eliminated from the system by hydrolytic extraction. The network polymer thus obtained exhibited cholesteric liquid crystalline organization when it was swollen in solvents.