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We report a new family of multiple responsive fluids based on the single-tailed pyrrolidone surfactants, N-ethyl-2-pyrrolidone N-alkyl amine (C(m)NP, where m = 10, 12, 14, 16, and 18). These surfactants are highly sensitive to solution pH as a result of the presence of the N-amino group in the molecules. Equilibrium surface tension results indicate that both the surface activity and micellization ability of C(m)NPs decrease with the increase of the protonation degree; i.e., they exhibit a higher critical micelle concentration (cmc) and higher surface tension at the cmc (γ(cmc)) at the acidic conditions than those at the basic conditions. The cmc values of C(m)NPs follow the well-known Klevens equation, which decrease linearly with the increase of the hydrocarbon chain length m at a given pH. More importantly, the self-assemblies of C(m)NPs are highly sensitive to pH, CO2, and CuCl2, as identified by turbidity and viscosity. The transitions between vesicles and wormlike micelles are further confirmed by rheology, static and dynamic light scattering (SLS and DLS), cryogenic transmission electron microscopy (cryo-TEM), and nuclear magnetic resonance (NMR) techniques systematically. Although the aggregate transitions induced by different factors are similar, however, the mechanisms are different. The pH- and CO2-induced transitions are attributed to variation in the protonation degree of the N-amino group; however, CuCl2-induced transitions are a result of the formation of C(m)NP and CuCl2 coordination complexes as revealed by two-dimensional (2D) nuclear Overhauser effect spectrometry (NOESY) NMR and ultraviolet-visible (UV-vis) spectra.

The self-assembly of novel Gemini surfactants with pyrrolidone head groups, N,N'-dialkyl-N,N'-di(ethyl-2-pyrrolidone) ethylenediamine (Di-C (n) P, where n = 6, 8, 10, 12), was studied systematically by employing UV-vis spectroscopy, fluorescence spectroscopy, NMR, dynamic light scattering (DLS), and cryo-transmission electronic microscopy (cryo-TEM) measurements. pH-induced spherical micelle-to-vesicle transitions (MVTs) were observed in all diluted Di-C (n) P aqueous solutions. Spherical micelles were formed when solution pHs were below 7.0, in which Di-C (n) Ps were 1:2 or 1:1 type cationic surfactants, whereas vesicles were formed instead at higher pHs, e.g., pH = 11.0, when Di-C (n) Ps were nonionic type. Apart from the pH-induced MVTs, concentration-induced MVTs were also observed in the protonated Di-C (n) P aqueous solutions due to counterion binding, indicating the presence of a second critical vesicle concentration (cvc) for ionic type Di-C (n) P. Furthermore, the cvc is decreased linearly with the number of carbon atoms n in the hydrophobic tail, following the well-known Stauff-Klevens rule, in the given protonation states.

A series of novel pH sensitive Gemini amphiphiles of N , N′ -dialkyl- N , N′ -di(ethyl-phthalimide) ethylenediamines (Di-C n Ph, n = 6, 8, 10, 12) was synthesized and characterized. It was found that relatively stable spread monolayers of Di-C n Ph can be formed at the air/water interface once n ⩾ 6, and their stability was improved by increasing the hydrophobic chain length or adding electrolyte. The surface pressure–area ( π – A ) isotherms of Di-C n Ph have been studied in detail by employing the axisymmetric drop shape analysis as penetration Langmuir balance. Furthermore, Brewster angle microscopy (BAM) was employed to confirm the monolayer phase transition from gaseous phase to liquid condensed phase via a liquid expanded phase. Moreover, dilatational rheological measurements of spread Di-C n Ph monolayers at the air/water interface were performed, and the influence of the hydrophobic chain length and pH on the dilatational elasticity ( e ) and viscosity ( η ) was also investigated. The results have suggested that the spread Di-C n Ph monolayers are spontaneously elastic.

A series of pH sensitive single-tailed surfactants, N-alkyl-1,2-ethylenediamine (CmN2N, where m = 8, 10, 12, 14, 16), were synthesized and characterized. The adsorption and aggregation properties of them were determined by equilibrium surface tension, static and dynamic light scattering (SLS and DLS), rheology, and cryogenic transmission electron microscopy (cryo-TEM) techniques in detail. It was found that both the surface activity and self-assembly behavior of CmN2N were strongly dependent on the solution pH, owing to the protonation state of amino groups in CmN2N. When at least one of the amino groups of CmN2N was protonated the logarithm of the critical micelle concentration (cmc) followed the well-known Klevens equation, i.e. cmc decreased linearly with the increase of hydrocarbon chain length. Simultaneously, the surface adsorption area per molecule (Amin) was decreased for each CmN2N when the solution pH varied from acidic to basic conditions. The pH-dependent micelle to vesicle transition was universally observed in the bulk phase of CmN2N. More interestingly, the rodlike micelles formed in C10N2N, C12N2N and C14N2N could transform into vesicles reversibly upon heating or cooling, which indicated the thermal sensitivityof organized assemblies, whereas not in C8N2N and C16N2N.

A new series of pH-responsive Gemini surfactants with 2-pyrrolidone head groups, N,N'-dialkyl-N,N'-di(ethyl-2-pyrrolidone)ethylenediamine (Di-C(n)P, where n = 6, 8 10, 12), were synthesized and characterized by (1)H NMR, (13)C NMR, ESI-MS, and elemental analysis. The surface activity and micellization behavior at acidic, neutral, and basic conditions were characterized by equilibrium surface tension and fluorescence techniques. It was found that the surface activity of Di-C(n)P depends on the pH of aqueous solutions due to the protonation state of surfactant molecules when pH was varied. The new compounds have lower cmc and γ(cmc) in comparison with that of m-2-m type conventional cationic Gemini surfactants and gluconamide-type nonionic Gemini surfactants. Fluorescence data confirm that micelles are formed when the concentration is above the cmc. Since micellization is of fundamental importance in surfactant applications such as solubilization, microemulsion, and related technologies, the significant difference in cmc at different pH of this new Gemini surfactant is employed to solubilize cyclohexane. The preliminary result indeed shows that the solubilization capacity of Di-C(n)P can be tuned by pH.

There are kinds of subsets in decontamination vehicle, complicated flow of work, high-precision controll, moving state operations, so traditional mechanical handling hydraulic circuit system can't meet the challenge. The paper directs toward the characteristic of hydraulic-drive system in decontamination vehicle. Electro-hydraulic proportional control technology and kernel-based on DPS processor, hydraulic-drive control system accomplishes reliable control to decontaminate works of the vehicle. The vehicle experiments indicate that control system meets standard of design and has absolute reliability.

A new family of gemini surfactants with pyrrolidinium head groups, 1,1′-(alkane-1, s-diyl)bis(1-dodecyl pyrrolidinium)bromide (C12–Cs–C12PB, s = 3, 4, 6, 8, 10, 12, 14, and 16), were synthesized. Their adsorption and micellization in aqueous solutions were investigated by various techniques such as equilibrium surface tension, fluorescence, and conductivity in detail. It was found that the effect of the spacer length on surfactant aggregation in aqueous solutions is similar to that of the well-known gemini surfactants with quaternary ammonium head groups (m-s-m), whereas the occupied limiting area per molecule (Amin) at the surface increases linearly with s rather than going through a maximum value at a medium value of s like that of m-s-m. The thermodynamic parameters suggest that the micellization of C12–Cs–C12PB is an entropy driven process regardless of the spacer length s. Moreover, a second breakpoint appeared in both γ–log c and I1/I3–c curves of C12–C14–C12PB and C12–C16–C12PB as the surfactant concentration increases, which can be attributed to the formation of larger aggregates. The morphology of the aggregates is confirmed by employing dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM) techniques.