Solvent Affinity Research Articles

Comparative Study of the Chemical Characterisation of Bioactive Compounds in Different Fractions of Ethanol Extract of Amaranthus Spinosus Leaves

In the evolution of pharmaceutical research, and to discover novel drugs, as well as therapeutic agents the exploration of plant-derived secondary metabolites offers a promising avenue. The current investigation has identified several phytochemicals in the various fractions of the sample being studied. Comparative study on the fractions showed certain phytocompounds were soluble in the solvents of fractionation. Compounds such as n-Hexadecenoic acid, Phthalic anhydride, Dodecanoic acid had affinity for both solvents, however, in varying concentrations as they were more abundant in the n-Hexane fraction. The result of the GCMS showed the presence of 12 compounds in the n-Hexane fraction, with the most abundant being cis-Vaccenic acid (40.39 %), n-Hexadecanoic acid (13.21 %), 9,12-Octadecadienoic acid (Z, Z)- (11.52 %), Octadecanoic acid (10.33 %), and Linoelaidic acid (9.84 %), which are reported to exhibit various biological activities. The FTIR analysis of this fraction further revealed functional groups such as Alcohol, Carboxylic acid, Alkene, Alkane, Aldehyde, Carbon dioxide, Nitrile, Allene, conjugated alkene, phenol, and Alkyl & Aryl Halides. GC-MS result of chloroform fraction further revealed the presence of 13 phytochemical compounds, of which the abundant phytochemical compounds are Linoelaidic acid (32.99 %), Z,Z-10,12-Hexadecadien-1-ol acetate (17.12 %), Nonanoic acid (14.81 %), and Cyclohexene, 4-pentyl-1-(4-propylcyclohexyl)- (12.08 %), while the FT-IR result showed the presence of sixteen (16) peaks, with functional groups such as Alcohols, phenols, thiol, thiocyanate, and δ-lactone. This study therefore infers that the pharmacological potential of the plant may be linked to the presence of the bioactive compounds in it as revealed by this study, however, recommended further study to identify the pharmacological activity of the other compounds with unknown activities, explore more pharmacological activities of the known compounds to solidify the claims on them further, and further carry out toxicity studies on the compounds to ascertain their safety.

Evaporation-Induced Switching from Flocculated to Dispersed TiO2 Nanoparticles in Binary Solvents.

Evaporation in mixed solutions containing both volatile and involatile solvents changes the properties of the binary solvent. We found that evaporating one solvent drastically increased the affinity of the mixed solvent to dispersant molecules and induced a switch from flocculated to dispersed TiO2 nanoparticles (TiO2NPs). We prepared dispersions of TiO2NPs with mixtures of volatile cyclosiloxane (Dx), involatile polar oil, and a dispersant, namely polyhydroxystearic acid (PHSA). Dx is a nonsolvent but the polar oil is a good solvent for PHSA. The dispersions were applied on a quartz substrate, and Dx was evaporated. The original applied films were turbid, in which flocculated TiO2NPs formed network structures. However, as the evaporation of Dx progressed, the drying films became transparent and the network structures of TiO2NPs loosened and disappeared. After the evaporation of Dx, the applied films were transparent to visible light but blocked the transmission of UV light. The flow characteristics of the dispersions also changed. The original dispersions showed shear-thinning but became more Newtonian-like as the fraction of Dx decreased. Generally, particles are concentrated in drying dispersions and become packed or flocculated as evaporation progresses. Our findings show that initially flocculated nanoparticles can be redispersed after evaporating a specific solvent. The effects of different Dxs and compositions on the switch from flocculated to dispersed TiO2NPs and their applicability as sunscreens are discussed.

Selective Cleavage and Structural Stability of Double Crosslinked Aromatic Polyamide Porous Materials

AbstractA porous, crosslinked aromatic polyamide having COCl and COOH groups (referred to as PA herein) prepared had a mesoporous structure and comprised agglomerates of particles with average diameters of approximately 30 nm. The PA was found to swell with significant deformation in response to water vapor, but was almost unchanged after exposure to toluene vapor. The polymeric structure returned to its original porous morphology after removal of the solvents, demonstrating that the PA possessed affinity for specific solvents and shape memory. The chemical composition and porous structure of the PA were also not affected by heating to 330 °C. The COCl groups in the PA could be modified by reaction with 2,4,6‐triaminopyrimidine (TAP), resulting in a doubly crosslinked structure based on the reaction with the TAP as well as the existing amide moieties in the polymer. The degree of modification was highly dependent on the reaction solvent used. The porous structure of the PA was essentially unchanged after this modification. The TAP‐based crosslinks in the modified PA could be selectively cleaved along with vaporization of the TAP by heating at 330 °C, which no change to the porous structure. Thus, the PA showed excellent heat resistance and structural stability.

Research of the anti-static and corrosion resistance of S-ZnO/m-SWCNTs/ FC composite coating

Abstract In order to solve the hazards caused by corrosion and charge accumulation in aircraft, electronic equipment, oil and gas pipelines, the corrosion resistance and anti-static performance of coatings need to be noted. In this study, monodisperse single-walled carbon nanotubes functional slurry (m-SWCNTs) was obtained by the combination of high-energy ultrasonic dispersion and non-covalent amphiphilic dispersant (PVP). In this way, the uniform dispersion of low-content m-SWCNTs in fluorocarbon composite coatings was achieved, and the micronano structured surface of the fluorocarbon composite coating was constructed by using the modified-ZnO in order to achieve superhydrophobicity. The results showed that the corrosion resistance of the fluorocarbon composite coating was further improved and the antistatic property of the composite coating met the use requirements, which was achieved through the synergistic effect of the m-SWCNTs network and the modified-ZnO. The resistivity of S-ZnO/m-SWCNTs/FC coating is 3.15 Ωm, acting as anti-static coating to reduce safety hazards, its corrosion current is 9.66×10−8 A/cm2, which is lower than bare steel by 3 orders of magnitude. Meanwhile, the composite coating owns the self-cleaning, superhydrophobic and organic solvent affinity, acting as oil-water separation coating. This research provides a new idea for the fabrication of multifunctional coating, elucidating the significant potential of its applications.

Assessment of Solvent Extraction using Sonication to Recover Tryptophan from Kappaphycus alvarezii (Doty) Doty ex Silva: Experimental and Modelling

The application of Kappaphycus alvarezii in the food system has attracted researchers due to its bioactive compounds, including tryptophan. The present study was conducted to extract tryptophan from K. alvarezii with the aid of sonication. A reduced multilevel factorial design was conducted to evaluate the effect of solvent, ultrasound power, duty-pulse cycle, time and temperature on the recovery of tryptophan. Analysis of variance suggested that the type of solvent and combination setting of power and duty-pulse cycle significantly influenced the extraction (p < 0.05). In contrast, extraction time and temperature did not alter the extraction (p > 0.05). The optimum was using ethanol, ultrasound power 80 %, pulse duty-cycle 0.8 s–1, extraction time 10 min, and temperature 25 °C and tryptophan concentration was 56.41 ± 2.42 mg L–1. Subsequently, a COnducto-like Screening MOdel for Real Solvent (COSMO-RS) was performed to clarify the impact of solvent affinity and polarity on the tryptophan extraction from K. alvarezii.

Impact of Nonsolvent–Solvent Affinity on Membrane Morphology and Microstructure: Unraveling the Transition from Traversing Pore to Closed Void Structures

Impact of Nonsolvent–Solvent Affinity on Membrane Morphology and Microstructure: Unraveling the Transition from Traversing Pore to Closed Void Structures

Morphological Transitions of Block Copolymer Micelles: Implications for Mesoporous Materials Ordering

AbstractThe design of block‐copolymer‐based functional materials, including mesoporous membranes and nanoparticles, requires a comprehensive understanding of the hierarchical assembly of block copolymers in selective solvents into micelles and subsequent ordered phases. It is hypothesized that micellar ordering and characteristic assembly can be described using a set of phase parameters that account for entropic and enthalpic interactions. Dissipative particle dynamics (DPD) simulations are used to systematically investigate the self‐assembly of semidiluted block copolymers, resembling isoporous membrane preparation conditions. The effect of Flory–Huggins interaction parameters, block lengths, and concentration on the morphology and polydispersity of the micelles is evaluated. The interaction parameters are mapped into Flory–Huggins theory by considering the block's conformation. These results reveal the effect of polymer concentration and solvent affinity on the morphological transition of the aggregates, in agreement with existing experimental evidence. It is identified that monodisperse‐spherical micelles in solution are fundamental to stabilize ordered states. Weak solvent segregation of the largest block, curvature of the core‐corona interface, and stretching of the corona‐forming one are found to be key to stabilize monodisperse assemblies. These conditions can be predicted using spherical‐micelles packing considerations and a global phase parameter from the Flory–Huggins theory. This study provides valuable insights into the self‐assembly of diblock copolymers and offers a potential way to optimize the preparation of mesoporous ordered structures and micelle ordering in semidiluted systems.

Conductive PEDOT-Dominant Surface of Transparent Electrode Patch via Selective Phase Transfer for Efficient Flexible Photoelectronic Devices.

In this study, a conductive patch for a flexible organic optoelectronic device is proposed and implemented using a poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) polymer electrode based on a transfer process to achieve its high conductivity with an efficient conductive pathway. This PEDOT-dominant surface is induced by phase inversion during the transfer process owing to the solvent affinity of the PSS phase. The PEDOT:PSS patch formed by the transfer process minimizes the power loss in a flexible optoelectronic device due to the improved charge collection and suppressed leakage current responses. In addition, the bending stability of the flexible photoelectronic device is also enhanced by maintaining performance for 1000 bending cycles. Therefore, in the fabrication of a transparent flexible conductive PEDOT:PSS patch, the transfer process of a conducting polymer constitutes an effective strategy that can improve conductivity and embellished morphology.

The physical basis for solvent flow in organic solvent nanofiltration.

Organic solvent nanofiltration (OSN) is an emerging membrane technology that could revolutionize chemical separations in numerous vital industries. Despite its significance, there remains a lack of fundamental understanding of solvent transport mechanisms in OSN membranes. Here, we use an extended Flory-Rehner theory, nonequilibrium molecular dynamic simulations, and organic solvent transport experiments to demonstrate that solvent flow in OSN membranes is driven by a pressure gradient. We show that solvent molecules migrate as clusters through interconnected pathways within the membrane pore structure, challenging the widely accepted diffusion-based view of solvent transport in OSN. We further reveal that solvent permeance is dependent on solvent affinity to the OSN membrane, which, in turn, controls the membrane pore structure. Our fundamental insights lay the scientific groundwork for the development of next-generation OSN membranes.

Intrinsically microporous polyimide membranes with synergistic aromatic and alicyclic linking groups for efficient molecular separation

Polymers of intrinsic microporosity (PIMs) are widely recognized for having great potential in reforming membrane technology for molecular separation within organic solvents, due to their rich and appropriate pore structures with a size < 2 nm. However, the swelling in organic solvents has a significant effect on their pore structures due to the amorphous and linear nature, resulting in the permeability and selectivity performances of developed PIM membranes being far from ideal. In this work, we synthesized an advanced polyimide of intrinsic microporosity by integrating a Tröger’s base (TB) structure with an synergistic structure of aromatic (naphthalenediimide, NDI) and alicyclic (bicyclooctenediimide, BCODI) linking groups. The TB with a rigid and twisted structure was used to furnish a basis for inhibiting chain packing for high overall free volume. The ultra-rigid NDI units maintained such a tailored high free volume and provided superior solvent resistance. The relatively flexible and polar BCODI units promoted local chain mobility to tailor uniform pore size distribution and increased affinity for polar solvents. The innovative design fostered the formation of stable, uniform, and highly solvent-accessible intrinsic micropores. The prepared TFC membrane exhibited good organic solvent separation capabilities, achieving an ethanol permeance of 7.6 L m-2 h−1 bar−1 and a low molecular weight cut-off (MWCO) of approximately 470 Da. This work contributes significantly to the strategic design of PIMs for preparing high-performance membranes for realistic chemical-related separation application scenarios.

Observation of Solvent-Dependence in the Mechanism of Neutral-Catalyzed Isomerization of para-Aminobenzoic Acid Protomers.

Proton-transfer reactions are commonplace during electrospray ionization (ESI) mass spectrometry experiments and are often responsible for imparting charge to analyte molecules. Multiple protonation-site isomers (protomers) can arise for polyfunctional molecules and these isomers can interconvert via solvent-mediated proton transfer reactions during various stages of the ESI process. Studying the populations and interconversion of protonation isomers provides key insight into the ESI process, ion-molecule interactions, and ion dissociation mechanisms. An archetype molecule to study protomer interconversion fundamentals in this context is para-aminobenzoic acid (pABA), where both the amino and carboxylic acid protomers are typically formed under ESI and the mechanisms for interconversion are still under refinement. Using ion-trap mass spectrometry reaction kinetics (2.5 mTorr, 300 K), this study examines gas-phase interconversion catalysis of pABA protomers by seven neutral species, which are commen solvents and additives used for ESI: water, formic acid, methanol, ethanol, propanol, ammonia, and acetonitrile. Three distinct reaction cases are reported: (i) formic acid, methanol, ethanol, propanol, and ammonia each catalyze the interconversion between the amino and carboxylic acid protomers via a n = 1 solvent-molecule vehicle mechanism; (ii) for water, however, a n = 6 adduct complex is detected and this suggests that the observed protomer interconversion occurs through a Grotthuss mechanism, in accord with literature reports; (iii) acetonitrile inhibits proton transfer by the formation of particularly stable n = 1 and 2 adduct complexes. The second-order rate constants for the protomer interconversion are observed to increase in the following order: H2O < HCO2H < MeOH < EtOH < PrOH < NH3. Potential energy schemes are reported for all neutral-catalyzed proton transfer reactions using the DSD-PBEP86-D3(BJ)/aug-cc-pVDZ level of theory. A central transition state, which connects the protonation site adducts, is shown to be the key rate-limiting step. The energy of this transition state is sensitive to the proton affinity of the neutral solvent, and this is supported by the correlation between the reaction rate and the solvent proton affinity.

Green recovery of platform chemicals from hydrothermal carbonization process water

This study explores the side-recovery of platform chemicals in the hydrothermal carbonization waste-to-energy chain. Up to 90 % of target chemicals, furfural and 5-hydroxymethylfurfural, were green extracted from the process waters using the hydrophobic deep eutectic solvent decanoic acid/thymol. Wheat straw and rice husk reacted (1/4 solid/water ratio) for up to 120 min and at 180 and 230 °C. The dissolved chemicals built up to 5.9 g/L, accounting for 12 % of the total carbon. Extractions from the process waters and those from reference solutions behaved similarly. The solvent affinity toward furfural is 3.5 times higher than that of 5-hydroxymethylfurfural. The aqueous raffinates chromatographic outline demonstrated the recyclability for prosecuting the HTC. Focused experiments mimicked the functioning of an industrial cascade of two crosscurrent mixer settlers. Extraction yields were 90.7 and 65.8 % for furfural and 5-hydroxymethylfurfural. The counterflow arrangement, simulated by the Kremser method, gave corresponding higher yields, 96.9 and 73.4 %, respectively.

Carotenoids production and extraction from Yarrowia lipolytica cells: A biocompatible approach using biosolvents

The use of carotenoids, pigments with significant importance in the food and pharmaceutical industries, has been widely recognized because of their functions as colorants and antioxidants. The production of carotenoids from oleaginous yeasts is an efficient and eco-friendly alternative to that of synthetic carotenoids. Yarrowia lipolytica, due to its ability to synthesize high-value-added compounds, including carotenoids and lipids, has emerged as a promising biotechnological platform for this purpose. This study aimed to evaluate the efficiency of biosolvents for carotenoid extraction with the goal of replacing toxic organic solvents that pose risks to both human health and the environment. The Solid-Liquid Extraction (SLE) technique was employed to disrupt the rigid cell wall and extract intracellular pigments. Subsequent extractions were conducted using a 2:3:1 (w/w/w) ratio of ethanol:ethyl acetate:water, resulting in a total β-carotene concentration of approximately 5 mg β-carotene equivalent/g dry biomass. The COSMO-SAC model was utilized to elucidate the solute–solvent affinity, and the results obtained were consistent with the experimental findings. To improve the process, various ratios of biosolvents were investigated, and a subsequent Solid-Liquid-Liquid Extraction (SLLE) was introduced. Process integration and adjustments to the mixed biosolvent composition achieved yields ranging from 50 to 100 % in just four consecutive extractions. The proposed integrative platform not only enhances the efficiency of the extraction process but also enables the fractionation and purification of bioproducts from Y. lipolytica cells, thereby maximizing their biotechnological potential.

Uniform, convex structuring of polymeric colloids via site-selected swelling

Non-spherical, polymeric colloids serve as building blocks for advanced functional materials. We propose a novel method to produce morphologically controlled, non-spherical particles by generating site-selected, convex structures on polystyrene (PS) particles. It consists of two simple procedures: a monolayer of PS particles is illuminated with UV light and is subsequently immersed in a fluorinated solvent (HFIP). UV irradiation generates site-selected, oxidized domains on PS particles with a different solvent affinity than unoxidized PS, and HFIP immersion preferentially swells the oxidized domains. Such swelling gives rise to site-selected, convex structures on PS particles. By adjusting UV irradiation conditions, including incident and azimuth angles, the oxidized sites, i.e., the swelled portions, can be accurately situated, allowing us to produce various convex shapes, including chiral shapes at desired positions on PS particles.

Synthetic asphaltene for green carbon material

We have synthesized a mixture of hydrocarbons with characteristic of petroleum asphaltene, which is the heaviest fraction in petroleum and source for carbon materials. The synthesized asphaltene (SA) shows identical solvent affinity with various organic solvents as native asphaltene (NA), and the chemical structure distribution, molecular weight, and size in solution are all within those of NA. Furthermore, SA exhibited similar aggregation structure, melting behavior, and decomposition behavior as NA. The mixture consists of C84H76 (Mw 1085.5) and C84H78 (1087.5); the former comprises a structure with 17 aromatic rings and two C12H25 side chains, and the latter consists of a pair of interconnected configurations, each with 8 aromatic rings and a singular C12H25 side chain. A synthetic method for petroleum asphaltene was found, which allowed us to propose a synthetic route from biomass-derived feedstock.

Mechanism of PVDF Membrane Formation by NIPS Revisited: Effect of Precipitation Bath Nature and Polymer-Solvent Affinity.

A new interpretation of the mechanism of the polyvinylidene fluoride (PVDF) membrane formation using the nonsolvent-induced phase separation (NIPS) method based on an analysis of the complete experimental phase diagram for the three-component mixture PVDF-dimethyl acetamide (DMAc)-water is proposed. The effects of the precipitation bath's harshness and thermodynamic affinity of the polymer's solvent on the morphology, crystalline structure, transport and physical-mechanical properties of the membranes are investigated. These characteristics were studied via scanning electron microscopy, wide-angle X-ray scattering, liquid-liquid porosimetry and standard methods of physico-mechanical analysis. It is established that an increase in DMAc concentration in the precipitation bath results in the growth of mean pore size from ~60 to ~150 nm and an increase in permeance from ~2.8 to ~8 L m-2 h-1 bar-1. It was observed that pore size transformations are accompanied by changes in the tensile strength of membranes from ~9 to ~11 and to 6 MPa, which were explained by the degeneration of finger-like pores and appearance of spherulitic structures in the samples. The addition of water to the dope solution decreased both the transport (mean pore size changed from ~55 to ~25 nm and permeance reduced from ~2.8 to ~0.5 L m-2 h-1 bar-1) and mechanical properties of the membranes (tensile strength decreased from ~9 to ~6 MPa). It is possible to conclude that the best membrane quality may be reached using pure DMAc as a solvent and a precipitation bath containing 10-30% wt. of DMAc, in addition to water.

Solvent Acts as the Referee in a Match-Up Between Charged and Preorganized Receptors.

The prevalence of anion-cation contacts in biomolecular recognition under aqueous conditions suggests that ionic interactions should dominate the binding of anions in solvents across both high and low polarities. Investigations of this idea using titrations in low polarity solvents are impaired by interferences from ion pairing that prevent a clear picture of binding. To address this limitation and test the impact of ion-ion interactions across multiple solvents, we quantified chloride binding to a cationic receptor after accounting for ion pairing. In these studies, we created a chelate receptor using aryl-triazole CH donors and a quinolinium unit that directs its cationic methyl inside the binding pocket. In low-polarity dichloromethane, the 1 : 1 complex (log K1 : 1 ~ 7.3) is more stable than neutral chelates, but fortuitously comparable to a preorganized macrocycle (log K1 : 1 ~ 6.9). Polar acetonitrile and DMSO diminish stabilities of the charged receptor (log K1 : 1 ~ 3.7 and 1.9) but surprisingly 100-fold more than the macrocycle. While both receptors lose stability by dielectric screening of electrostatic stability, the cationic receptor also pays additional costs of organization. Thus even though the charged receptor has stronger binding in apolar solvents, the uncharged receptor has more anion affinity in polar solvents.

A Computational Chemistry Approach to the Molecular Design of SiO2 Nanoparticles Coated with Stearic Acid and Sodium Stearate in Ethanol Solvent.

Preparation of hydrophobic SiO2 nanoparticles (NPs) coated with different surfactants is important due to their potential application in different fields of chemistry. In this work, a combined experimental and Molecular Dynamics (MD) simulation approach, is advanced to characterize the adsorption process, in ethanol as a solvent, of stearic acid and sodium stearate on SiO2 spherical NPs with different ionization degrees (0%, 10%, and 23.3%). The main objective is to gain molecular insight into the factors involved in the preparation of hydrophobic coated NPs, which involves the intervention of ion-dipole, electrostatic, and hydrogen bond-type interactions depending on the surfactants and the nature SiO2 NPs. Our results demonstrate that the SiO2 NPs have a good affinity for ethanol solvent medium., as confirmed through the analysis of the Radial Distribution Functions (RDFs)), which indicates that hydrogen bonds are formed at a distance of ∼0.192 nm between ethanol and SiO2 NPs. The presence of Na+ ions reduce the electrostatic repulsion between the -COO- and -SiO- groups in NPs with degrees of ionization of 10% and 23.3%, because it acts as a bridge and thus favors the adsorption between the silanol and carboxylic groups. The investigation of the Potentials of Mean Force (PMFs) suggests that the adsorption on these NPs, is a spontaneous process compared with the case with 0% ionization degree. The experimental coating of the NPs was studied using Atomic Force Microscopy (AFM), a technique that allows the indirect measure of the Work of Adhesion (Wadh), a key quantity to estimate the energy needed to separate the interfaces AFM tip-sample. The experimental values of Wadh for the pure SiO2 NPs and two modified SiO2 NPs correspond to 2.01 J/m2, 1.72 J/m2 and 1.43 J/m2, respectively. The main conclusion is that the interaction energies between surfactants and SiO2 NPs, estimated from MD simulations, and the Wadh obtained from AFM measurements are correlated, in the sense that the reduction in the Wadh, in a solvent-free environment, corresponds to an increment of the interaction energy in the presence of the solvent. This reduction in Wadh is also associated with the fact that the nature of the coating of the SiO2 NPs surfaces increases the NPs hydrophobicity. Our analysis provides a path for the computational design and the prediction of hydrophobicity of coated NPs, which is the main focus of our work.

Molecular weight resolution of solvent resistant nanofiltration (SRNF) membranes

Engineering membranes for molecular separations in organic media is still a big challenge, especially when two closely resembling solutes have to be separated by allowing one to pass with the solvent and the other to be rejected. The so-called “resolution” of the membrane then becomes critical. Resolution reflects the difference in rejection values of the two (or more) solutes for that solvent-membrane system. Recently developed crosslinked poly(vinylidene difluoride) (XL-PVDF) and well-known crosslinked polyimide (XL-PI) membranes were prepared and tested for solvent resistant nanofiltration (SRNF). Rejections of 7 dyes (i.e. Rose Bengal (RB), Acid fuchsin (AF), Rhodamin B (RhB), Sudan Black (SB), Zinc tetraphenylporphyrin (ZTPP), and 55,10,15,20-Tetrakis(3,5-di-tert-butyl phenyl)porphyrin (TBPP) in a broad range of solvents, i.e. a set of polar solvents (water, ethanol, isopropanol), and a set of non-polar ones (butyl acetate, chloroform, xylene and toluene) were studied. As anticipated, the molecular weight cut-offs (MWCOs) of both membrane-types varied with the applied solvent type. Butyl acetate and chloroform filtrations respectively yielded the sharpest MWCO for XL-PVDF and XL-PI. The varying MWCO-curve per solvent is explained by the changing affinity of solvents and solutes for the membrane, as indicated by swelling and sorption experiments respectively.

Thermo‐Responsive Ultrafiltration Block Copolymer Membranes Based on Polystyrene‐block‐poly(diethyl acrylamide)

AbstractWithin the present work, a thermo‐responsive ultrafiltration membrane is manufactured based on a polystyrene‐block‐poly(diethyl acrylamide) block copolymer (BCP). The poly(diethyl acrylamide) block segment features a lower critical solution temperature (LCST) in water, similar to the well‐known poly(N‐isopropylacrylamide), but having increased biocompatibility and without exhibiting a hysteresis of the thermally induced switching behavior. The BCP is synthesized via sequential “living” anionic polymerization protocols and analyzed by 1H‐NMR spectroscopy, size exclusion chromatography, and differential scanning calorimetry. The resulting morphology in the bulk state is investigated by transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) revealing the intended hexagonal cylindrical morphology. The BCPs form micelles in a binary mixture of tetrahydrofuran and dimethylformamide, where BCP composition and solvent affinities are discussed in light of the expected structure of these micelles and the resulting BCP membrane formation. The membranes are manufactured using the non‐solvent induced phase separation (NIPS) process and are characterized via scanning electron microscopy (SEM) and water permeation measurements. The latter are carried out at room temperature and at 50 °C revealing up to a 23‐fold increase of the permeance, when crossing the LCST of the poly(diethyl acrylamide) block segment in water.