Hydrophobic Spacer Research Articles

Studies on physicochemical properties of three Gemini surfactants with different spacer groups

Three Gemini surfactants with the same hydrophobic chain but different spacer groups, including two cationic Gemini surfactants (CGS and CGS-O) and a zwitterionic Gemini surfactant (ZGS-S), were synthesized, and their chemical structures were characterized by FT-IR and 1H NMR. The effect of spacer group on surface/interface activity, interfacial tension at the oil-water interface, wetting ability, electrolytes tolerance and thermal stability was determined. The results showed the structure of spacer group has a certain influence on the surface/interface activity. Among the three Gemini surfactants, ZGS-S has the strongest ability to reduce surface tension, followed by CGS-O. Three Gemini surfactants can reduce the oil-water interfacial tension to ultra-low value, but the time required to reach the minimum value is different, indicating that the surfactant molecules move at different adsorption rates from solution to the interface. This phenomenon is also confirmed by dynamic surface tension and dynamic contact angle tests. Compared with CGS, CGS-O molecules move slower in the solution, while the adsorption rate of ZGS-S on the interface surpasses that of CGS near the critical micelle concentration. Among the three Gemini surfactants, the electrolytes tolerance of ZGS-S is the strongest, while CGS-O is the lowest. The introduction of sulfate group in spacer group reduces the thermal stability of Gemini surfactant.

A Molecular Approach to Control the Morphology and Properties for the Development of Highly Conductive and Stable Anion Exchange Membranes

Anion exchange membrane fuel cells (AEMFCs) have drawn growing interests in the past decade.The inexpensive non-platinum group metal (non-PGM) catalyst and faster oxygen reduction reactions (ORRs) kinetic at high pH are the potential driving force to develop AEM materials.Despite numerous studies, molecular design rules have not yet been fully elucidated for the development of highly conductive and alkaline stable AEMs. Polymer materials that can produce tunable nanoscale and well-developed micro-phase separated morphology hold great promises as highly conductive and alkaline stable AEMs.Understanding the relationship between the structure and electrical/physicochemical properties of the corresponding AEMs are critical to the rational design and development of AEMs.We report herein a systematic approach to develop highly conductive and alkaline stable anion exchange membranes based on the non-(aryl ether) polymer backbone grafted with the pendant quaternary ammonium as an ion-conducting head group and the alkyl chain as a hydrophobic spacer in different ways. The effects of structure on the properties of the corresponding AEMs such as morphology, ion conductivity, physicochemical properties, and fuel cell properties will be investigated in detail.

Uncharged Gemini-Amphiphiles as Components of Cationic Liposomes for Delivery of Nucleic Acids

New uncharged gemini-amphiphiles have been synthesized. A series of cationic liposomes based on the polycationic amphiphile 1,26-bis(cholest-5-en-3β-yloxycarbonylamino)-7,11,16,20-tetraazahexacosan tetrahydrochloride (2X3), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and uncharged gemini-amphiphiles that contain short hydrophobic and long hydrophilic spacers have been prepared. The physicochemical characteristics, cytotoxicity, and transfection activity of cationic liposomes have been studied. Cationic liposomes that include 10% (mol) of a uncharged gemini-amphiphile with the oligooxymethylene spacer have formed small complexes with plasmid DNA and efficiently delivered it into eukaryotic cells.

Selective Convergence to Atropisomers of a Porphyrin Derivative Having Bulky Substituents at the Periphery.

Four kinds of possible atropisomers of a porphyrin derivative (1), having mesityl groups at one of the o-positions of each meso-aryl group, can be selectively converged to targeted atropisomers among the four isomers (αααα, αααβ, αβαβ, and ααββ) under appropriate conditions for each atropisomer. For example, protonation and subsequent neutralization of a free base porphyrin (H2-1) induces a convergence reaction to the αβαβ atropisomer, H2-1-αβαβ, from an atropisomeric mixture. The αααα isomer, H2-1-αααα, was also obtained by heating a solution of H2-1 in CHCl3 in 60% isolated yield, probably owing to a template effect of the solvent molecule. Remarkably, when an atropisomeric mixture of its zinc complex, Zn-1, was heated at 70 °C in a ClCH2CH2Cl/MeOH mixed solvent, crystals composed of only Zn-1-αααα were formed. The hydrophobic space formed by the four mesityl groups in the αααα isomer can be used for repeatable molecular encapsulation of benzene, and the encapsulation structure was elucidated by powder X-ray diffraction analysis. Heating the solid of an atropisomeric mixture of Zn-1 to 400 °C afforded the ααββ isomer almost quantitatively. On the other hand, the solid of H2-1-αααα can be converted by heating, successively to H2-1-αααβ at 286 °C and then to H2-1-ααββ at 350 °C.

Robust Grafting of Polyionenes: New Potent and Versatile Antimicrobial Surfaces.

Polyionenes (PI) with stable positive charges and tunable hydrophobic spacers in the polymer backbone, are shown to be particularly efficient regarding antimicrobial properties. This effect can be modulated since it increases with the length of hydrophobic spacers, i.e., the number of methylene groups between quaternary ammoniums. Now, to further explore these properties and provide efficient antimicrobial surfaces, polyionenes should be grafted onto materials. Here a robust grafting strategy to covalently attach polyionenes is described. The method consisted in a sequential surface chemistry procedure combining polydopamine coating, diazonium-induced polymerization, and polyaddition. To the best of knowledge, grafting of PI onto surfaces is not reported earlier. All chemical steps are characterized in detail via various surface analysis techniques (FTIR, X-ray photoelectron spectroscopy, contact angle, and surface energy measurements). The antibacterial properties of polyionene-grafted surfaces are then studied through bacterial adhesion experiments consisting in enumeration of adherent bacteria (total and viable cultivable cells). PI-grafted surfaces are showed to display effective and versatile bacteriostatic/bactericidal properties associated with a proadhesive effect.

Glypicans shield the Wnt lipid moiety to enable signalling at a distance.

A relatively small number of proteins have been suggested to act as morphogens-signalling molecules that spread within tissues to organize tissue repair and the specification of cell fate during development. Among them are Wnt proteins, which carry a palmitoleate moiety that is essential for signalling activity1-3. How a hydrophobic lipoprotein can spread in the aqueous extracellular space is unknown. Several mechanisms, such as those involving lipoprotein particles, exosomes or a specific chaperone, have been proposed to overcome this so-called Wnt solubility problem4-6. Here we provide evidence against these models and show that the Wnt lipid is shielded by the core domain of a subclass of glypicans defined by the Dally-like protein (Dlp). Structural analysis shows that, in the presence of palmitoleoylated peptides, these glypicans change conformation to create a hydrophobic space. Thus, glypicans of the Dlp family protect the lipid of Wnt proteins from the aqueous environment and serve as a reservoir from which Wnt proteins can be handed over to signalling receptors.

Assessing mobile ions contributions to admittance spectra and current-voltage characteristics of 3D and 2D/3D perovskite solar cells

Recently, the 2D perovskite layer is employed as a capping/passivating layer in the perovskite solar cells (PSCs). The 2D perovskite layer is prepared by inserting a large-sized hydrophobic cation spacer into the perovskite crystal lattice. The large-sized cation in the 2D perovskite lattice can successfully suppress the moisture intrusion and hence improve the stability of the PSCs. However, a deep understanding of the interfacial mechanisms at the 2D/3D heterojunction and the relative contributions of the mobile ions and trapped charge carriers is still lacking. In this work, deep levels transient spectroscopy (DLTS) and reverse DLTS (RDLTS) have been performed to characterize the n-i-p structured 3D and 2D/3D PSCs. DLTS and RDLTS have been used to distinguish between the spectral contribution made by mobile ionic species, electron/hole traps, and to investigate the presence of ordinary deep electron and hole traps in the bandgap of perovskite. Besides, the PSCs have been characterized by photoinduced voltage transient spectroscopy (PIVTS) to study the decay of the open-circuit voltage (VOC) under illumination. For both 3D and 2D/3D PSCs, the contribution of mobile ions was found to be dominant; however, in the case of 2D/3D samples, the intensity of the mobile ions signal was several times lower. The lower intensity can be correlated with a lower amplitude of slow tails in VOC decay curves in 2D/3D solar cells as compared to 3D solar cells. The PIVTS study also endorses the 2D/3D structures as more robust than the 3D structures.

Allosteric Coupling Between Drug Binding and the Aromatic Cassette in the Pore Domain of the hERG1 Channel: Implications for a State-Dependent Blockade.

Human-ether-a-go-go-related channel (hERG1) is the pore-forming domain of the delayed rectifier K+ channel in the heart which underlies the IKr current. The channel has been extensively studied due to its propensity to bind chemically diverse group of drugs. The subsequent hERG1 block can lead to a prolongation of the QT interval potentially leading to an abnormal cardiac electrical activity. The recently solved cryo-EM structure featured a striking non-swapped topology of the Voltage-Sensor Domain (VSD) which is packed against the pore-domain as well as a small and hydrophobic intra-cavity space. The small size and hydrophobicity of the cavity was unexpected and challenges the already-established hypothesis of drugs binding to the wide cavity. Recently, we showed that an amphipathic drug, ivabradine, may favorably bind the channel from the lipid-facing surface and we discovered a mutant (M651T) on the lipid facing domain between the VSD and the PD which inhibited the blocking capacity of the drug. Using multi-microseconds Molecular Dynamics (MD) simulations of wild-type and M651T mutant hERG1, we suggested the block of the channel through the lipid mediated pathway, the opening of which is facilitated by the flexible phenylalanine ring (F656). In this study, we characterize the dynamic interaction of the methionine-aromatic cassette in the S5-S6 helices by combining data from electrophysiological experiments with MD simulations and molecular docking to elucidate the complex allosteric coupling between drug binding to lipid-facing and intra-cavity sites and aromatic cassette dynamics. We investigated two well-established hERG1 blockers (ivabradine and dofetilide) for M651 sensitivity through electrophysiology and mutagenesis techniques. Our electrophysiology data reveal insensitivity of dofetilide to the mutations at site M651 on the lipid facing side of the channel, mirroring our results obtained from docking experiments. Moreover, we show that the dofetilide-induced block of hERG1 occurs through the intracellular space, whereas little to no block of ivabradine is observed during the intracellular application of the drug. The dynamic conformational rearrangement of the F656 appears to regulate the translocation of ivabradine into the central cavity. M651T mutation appears to disrupt this entry pathway by altering the molecular conformation of F656.

Solubilization mechanism of diesel in saponin micelle for contaminated montmorillonite washing

Abstract The biosurfactant was used to remove diesel from contaminated montmorillonite, which was enhanced by humic acid sodium salt (HASS) addition or microbubbles resulted from sonication. It was found that montmorillonite exhibited strong adsorption for saponin, causing the effective critical micelle concentration shift of saponin from 0.2 g L−1 to 0.6 g L−1. The washing efficacy (diesel removal) with 0.6 g L−1 saponin and 2% HASS (HASS/saponin ratio = 2%) increased 14.9 % compared to the control condition (without HASS), whereas the diesel removal with microbubble enhancement (25 min sonication) increased 15.2 % compared to the control condition. Bright-field microscopy, microscope, DLS, PSS, and TEM were used to measure the size of micelles and count micelle numbers. In the addition of 2% HASS, the mean diameter of saponin micelles decreased from 824.9 ± 12.3 nm to 91.3 ± 7.6 nm, and the number of micelles increased from 42,000 to 110,000 at saponin solution of 0.3 g L−1. The hydrophobic core volume increased accordingly. HASS molecule might cause the extension of hydrophobic interior space in micelles to solubilize the hydrocarbon contaminant. In addition to micelles solubilization, the microbubbles enhancement washing process increased the diesel removal by floatation, cavitation in sonication.

Polyion Complex Micelles for Protein Delivery Benefit from Flexible Hydrophobic Spacers in the Binding Group.

Although a range of polymer-protein polyion complex (PIC) micelle systems have been developed in the literature, relatively little attention has been paid to the influence of polymer structure on the assembly, or to the mechanism of disassembly. In this work, Förster resonance energy transfer is used in combination with light sheet fluorescence microscopy and isothermal calorimetry to monitor the formation and stability of PIC micelles with various carboxylic-acid-based binding blocks in MCF-7 cancer spheroid models. All micelles are stable in the presence of free protein, but are unstable in solutions with an ionic strength >200mm and prone to disassembly at reduced pH. Introducing carbon spacers between the backbone and the binding carboxylic acid results in improved PIC micelle stability at physiological pH, but also increases the pKa of the binding moiety, resulting in improved protein release upon cell uptake. These results give important insights into how to tune PIC micelle stability for controlled protein release in biological environments.

Nanoscale Coordination Polymer of Dimanganese(II) as Infinite, Flexible Nanosheets with Photo‐Switchable Morphology

An original co‐ligand association, consisting of 4,4'‐azopyridine and 1,3‐bis(carboxypropyl)tetramethyldisiloxane, is used for complexing MnII, to obtain a 2D dinuclear coordination array having infinite horizontal dimensions and nanometric thickness. Due to the shielding effect of the tetramethyldisiloxane units facing outwards on both sides, the sheets are free of any chemical or physical intermolecular interactions, as crystallographic analysis reveals. The compound shows two glass transitions, at –51 and 33 °C, and begins to decompose at 292 °C. The co‐existence in the structure of the highly hydrophobic tetramethyldisiloxane spacers and the polar metal complexed units confers amphiphilic character to the compound, making it capable of reducing the surface tension of the DMF, from 35.8 to 29.4 mN/m, at a critical micellar concentration around 1 wt.‐% complex. The presence of aggregates in solution is evidenced by dynamic light scattering. The light sensitive azopyridine units make the compound photo‐responsive. This behavior occurs both in solution as well as in the film, where the compound self‐assembles in micellar morphology when UV‐irradiated. Both conductivity and dielectric permittivity of the film increase as a result of trans–cis configuration. Magnetic measurement data indicate two antiferromagnetic coupled spins, S = 5/2, that are able to interact with small external magnetic field, i.e., during MFM scanning.

The Influence of Different Spacers on Biological Profile of Peptide Radiopharmaceuticals for Diagnosis and Therapy of Human Cancers.

Cancer is the leading cause of death worldwide. Early detection can reduce the disadvantageous effects of diseases and the mortality in cancer. Nuclear medicine is a powerful tool that has the ability to diagnose malignancy without harming normal tissues. In recent years, radiolabeled peptides have been investigated as potent agents for cancer detection. Therefore, it is necessary to modify radiopeptides in order to achieve more effective agents. This review describes modifications in the structure of radioconjugates with spacers who have improved the specificity and sensitivity of the peptides that are used in oncologic diagnosis and therapy. To improve the biological activity, researchers have conjugated these peptide analogs to different spacers and bifunctional chelators. Many spacers of different kinds, such as hydrocarbon chain, amino acid sequence, and poly (ethyleneglycol) were introduced in order to modify the pharmacokinetic properties of these biomolecules. Different spacers have been applied to develop radiolabeled peptides as potential tracers in nuclear medicine. Spacers with different charge and hydrophilicity affect the characteristics of peptide conjugate. For example, the complex with uncharged and hydrophobic spacers leads to increased liver uptake, while the composition with positively charged spacers results in high kidney retention. Therefore, the pharmacokinetics of radio complexes correlates to the structure and total charge of the conjugates. Radio imaging technology has been successfully applied to detect a tumor in the earliest stage. For this purpose, the assessment of useful agents to diagnose the lesion is necessary. Developing peptide radiopharmaceuticals using spacers can improve in vitro and in vivo behavior of radiotracers leading to better noninvasive detection and monitoring of tumor growth.

Hydrophobic pore space constituted in macroporous ZIF-8 for lipase immobilization greatly improving lipase catalytic performance in biodiesel preparation

BackgroundDuring lipase-mediated biodiesel production, by-product glycerol adsorbing on immobilized lipase is a common trouble that hinders enzymatic catalytic activity in biodiesel production process. In this work, we built a hydrophobic pore space in macroporous ZIF-8 (named as M-ZIF-8) to accommodate lipase so that the generated glycerol would be hard to be adsorbed in such hydrophobic environment. The performance of the immobilized lipase in biodiesel production as well as its characteristics for glycerol adsorption were systematically studied. The PDMS (polydimethylsiloxane) CVD (chemical vapor deposition) method was utilized to get hydrophobic M-ZIF-8-PDMS with hydrophobic macropore space and then ANL (Aspergillus niger lipase) was immobilized on M-ZIF-8 and M-ZIF-8-PDMS by diffusion into the macropores.ResultsANL@M-ZIF-8-PDMS presented higher enzymatic activity recovery and better biodiesel production catalytic performance compared to ANL@M-ZIF-8. Further study revealed that less glycerol adsorption was observed through the hydrophobic modification, which may attribute to the improved immobilized lipase performance during biodiesel production and ANL@M-ZIF-8-PDMS remained more than 96% activity after five cycles’ reuse. Through secondary structure and kinetic parameters’ analysis, we found that ANL@M-ZIF-8-PDMS had lower extent of protein aggregation and twice catalytic efficiency (Vmax/Km) than ANL@M-ZIF-8.ConclusionsHydrophobic pore space constituted in macroporous ZIF-8 for lipase immobilization greatly improved lipase catalytic performance in biodiesel preparation. The hydrophobic modification time showed negligible influence on the reusability of the immobilized lipase. This work broadened the prospect of immobilization of enzyme on MOFs with some inspiration.

Effects of spacers within a series of novel folate-containing lipoconjugates on the targeted delivery of nucleic acids

Limitations regarding the targeted delivery of therapeutic nucleic acids into cancer cells can be overcome by developing a non-viral delivery system equipped with folate-containing conjugates. Here, we report the synthesis of novel folate-containing lipoconjugates (FLs), which differ by spacers between the hydrophobic domain and ligand (folic acid). FLs were incorporated into a liposome composed of the polycationic amphiphile 1,26-bis(cholest-5-en-3β-yloxycarbonylamino)-7,11,16,20-tetraazahexacosan tetrahydrochloride (2X3) and helper lipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). At low (2/1) nitrogen to phosphate (N/P) ratio, liposomes containing 0.5 mol% FL with a short hydrophobic spacer and 2 mol% FL with medium hydrophilic spacer were compared with control liposomes containing 2 mol% FL with a polyethylene glycol spacer and showed higher transfection efficiency than non-targeted liposomal formulations and the commercial agent Lipofectamine 2000. At an N/P ratio of 4/1, the transfection efficiency of FL-containing liposomes were correlated neither with FL content within the liposomes nor FL structure.

Hydrophobic-hydrophilic comb-type quaternary ammonium-functionalized SEBS copolymers for high performance anion exchange membranes

Poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS) triblock copolymers are prepared with 50% hexyl quaternary ammonium (HQA) and 20% alkyl chains of different chain lengths: C4 (50HQA-20C4-SEBS) and C12 (50HQA-20C12-SEBS). Their physicochemical and electrical properties are investigated for use as novel alkaline anion exchange membranes. In most other comb-type polymers, the alkyl chain is introduced as a hydrophilic spacer unit between the polymer backbone and conducting head group. In the current study, additional alkyl chains are grafted onto the SEBS polymer as hydrophobic side chains as well as typical hydrophilic side chains. Introduction of this extra hydrophobic alkyl spacer group is done to obtain well-connected morphology, increased free volume, enhanced water uptake and related conductivity, together with improved physicochemical properties of the membranes obtained. The results are compared with HQA-functionalized SEBS without the hydrophobic alkyl spacer group (50HQA-20C0-SEBS), and the effects of the alkyl chain lengths on the structure of polymers and physicochemical properties of the corresponding membranes are investigated.

Kinetics of photo-isomerization of azobenzene containing surfactants

We report on photoisomerization kinetics of azobenzene containing surfactants in aqueous solution. The surfactant molecule consists of a positively charged trimethylammonium bromide head group, a hydrophobic spacer connecting via 6 to 10 CH2 groups to the azobenzene unit, and the hydrophobic tail of 1 and 3CH2 groups. Under exposure to light, the azobenzene photoisomerizes from more stable trans- to metastable cis-state, which can be switched back either thermally in dark or by illumination with light of a longer wavelength. The surfactant isomerization is described by a kinetic model of a pseudo first order reaction approaching equilibrium, where the intensity controls the rate of isomerization until the equilibrated state. The rate constants of the trans-cis and cis-trans photoisomerization are calculated as a function of several parameters such as wavelength and intensity of light, the surfactant concentration, and the length of the hydrophobic tail. The thermal relaxation rate from cis- to trans-state is studied as well. The surfactant isomerization shows a different kinetic below and above the critical micellar concentration of the trans isomer due to steric hindrance within the densely packed micelle but does not depend on the spacer length.

Monovalent anion selective anion-exchange membranes with imidazolium salt-terminated side-chains: Investigating the effect of hydrophobic alkyl spacer length

Ion-conductive polymers having highly ordered and well-defined phase-separated structures are potential materials for use as monovalent anion-selective membranes (MASMs). In this work, to investigate the effect of hydrophobic spacers, four side-chain-type imidazolium salt-tethered poly(arylene ether sulfone) anion-exchange membranes (AEMs) with different alkyl spacer lengths (–CH2– number: 3, 6, 9, and 12) were fabricated for use in electrodialysis (ED). Our investigations using atomic force microscopy, small angle X-ray scattering and X-ray diffraction demonstrate that the extended alkyl spacers change the nano-phase-separated structures, with an increased ion cluster space ranging from 3.29 nm to 7.76 nm, resulting from increased immiscibility between the additional hydrophobic alkyl spacers and (i) the hydrophobic aromatic backbones and (ii) the hydrophilic ion-conductive groups. In addition, with the extension of the alkyl spacer, chloride (Cl−) ion conductivity at 25 °C decreases from 16.4 mS cm−1 to 11.4 mS cm−1 and water uptake is reduced to 12.8% (20 °C). It is found that the as-prepared AEM with a hexyl alkyl spacer shows the superior perm-selectivity (Cl−/SO42−) of 7.10 (separation efficiency: 70.3%), as compared with three others (3.48, 6.81, and 4.26). This work thus presents an efficient strategy to guide the architectural design of novel MASMs.

A novel multifunctional adsorbent synthesized by modifying acidified organo-montmorillonite with iron hydroxides

Multifunctional adsorbents based on montmorillonite (Mt) have been of highly concerns due to their unique 2D layer structures and impressive co-adsorption performances. To further enhance the support ability and reactivity, a strategy was developed in this study to enable the co-existence of porous nanosilica (PNS) and hydrophobic interlayer spaces in Mt structure, and a novel multifunctional adsorbent (iron modified-acidified organo-Mt, Fe-AOMt) was then synthesized, aiming to simultaneously remove hydrophobic contaminants, oxyanion contaminants and heavy metals in water. The combination of XRD, FTIR and TEM verified the co-existence of amorphous PNS and layered structure (containing intercalated surfactant) in the acidified organo-Mt (AOMt), and results of STEM-EDX revealed uniform distribution of Fe after the further introduction of Fe hydroxides to AOMt. Additionally, pore structure analyses suggested that the acid activation can obviously increase the pore volume and specific surface area of OMt. Batch adsorption experiments revealed that Fe-AOMt as a promising multifunctional adsorbent was able to effectively and simultaneously remove nitrobenzene, phosphate, and Cd(II) in the multi-contaminant system. The synergetic adsorption of phosphate and Cd(II) on Fe-AOMt suggested the formation of ternary surface complexes (≡Fe–P–Cd), while the pH-independent uptake of nitrobenzene was hardly influenced by adsorption of phosphate and Cd(II), implying dissimilar adsorption mechanisms. The co-adsorption mechanism on Fe-AOMt was further revealed via XPS. Our work provided a novel and efficient Mt-based multifunctional adsorbent with a newly-proposed structure, which was a preliminary exploration of diversifying locations and types of active sites in Mt structure.

Cationic Amphiphilic Alternating Copolymers with Tunable Morphology.

A series of ionic amphiphilic alternating copolymers were characterized via SAXS, TEM and DLS to help understand factors that could potentially affect self-assembly, including the degree of polymerization, the length of hydrophobic spacers between ionic units, the distance between charged groups and polymer backbone, solvent envrioment and counterions.

Cationic gemini surfactants containing both amide and ester groups: Synthesis, surface properties and antibacterial activity

Nine novel cationic gemini surfactants containing both amide and ester groups were synthesized through a three-step reaction. These surfactants have the general formula of CnH2n+1OOCCH2N+(CH2)2-(CH2)3-NHOC-(CH2)m-CONH-(CH2)3-N+(CH2)2CH2COOCnH2n+1 (with n = 8, 10, 12 and m = 2, 3, 4), named BEQA-n, PEQA-n and HEQA-n (B, P, H correspond to surfactants of m = 2, 3, 4 and n = 8, 10, 12, respectively). Chemical structures, surface activity, cleavable properties, electrolytes tolerance, foam properties and antibacterial activity of these surfactants were successively investigated. The results show that the surfactants have lower critical micelle concentration (CMC) than traditional monomer surfactants. The values of CMC and the degree of counter ion dissociation (α) depend on the lengths of hydrophobic chain and spacer. The values of Krafft temperatures (Kt < 0 °C) and the standard Gibbs free energy (∆G0mic < 0) indicate that all surfactants have good water solubility and micelle-forming ability. The simultaneous presence of the amide and ester groups makes these surfactants have good hydrolytic ability in both basic and the acidic solutions. In addition, the surfactants exhibit greater electrolyte tolerance to NaCl than CaCl2. It is worth mentioning that EQA-8 and PEQA-12 have 200 g/L NaCl tolerance. Moreover, all of the surfactants have certain antibacterial activity against Gram-positive bacteria (S. aureus ATCC 25923) and Gram-negative bacteria (E. coli ATCC 25922), and the surfactants with hydrophobic chain length n = 10 have the strongest antibacterial activity.