盐水振荡与液膜振荡耦合

为进一步增大盐水振荡产生的电势差,并使盐水振荡可逆，该文将液膜振荡与盐水振荡耦合，组成一个耦合的振荡器.实验结果发现:(1)由于两振荡器耦合形成共振，所以此耦合振荡器的振幅明显增大; (2)耦合后的化学振荡器变为可逆振荡器.耦合振荡机理如下:扩散过程中形成的缔合物存于油相，难溶于水，通电后缔合物发生解离，因此造成反扩散，形成可逆振荡，且可逆程度及逆反应产生的电势差（即振幅）大大提高，扩展了盐水振荡在二次电池开发方面的应用.     

聚乙二醇对振荡反应的影响

前文［1］曾指出，生物体系的化学振荡反应实际上是产生于水溶胶之中（包括高分子溶液及表面活性剂溶液）．作为反应介质，水溶胶对生物体系的周期现象有着不可忽略的重要作用．因此，要模拟生物体系的化学振荡就不能不考虑溶胶对振荡反应的影响．前文［2，3］报道了表面活性剂TritonX－100（简称TX－100），TritonX－305等对振荡反应的影响．为了解聚乙二醇类表面活性剂中EO链的作用及高分子溶液对振荡反应的特征影响，我们选用高分子聚乙二醇（PEG）作为添加剂，考虑由于它的加入而引起振荡反应的变化．为了减少PEG中自由羟基的还原…     

乳液引起的Daniell电池中的电化学振荡

由油酸的煤油溶液与NaOH和CTAB两水溶液混合制成O/W型乳液.实验发现,此乳液的加入可使丹尼尔电池产生电池反应与电极反应的明显振荡现象.自发过程结束后,通以2 V, 50 Hz或100 Hz交流电4 h,则此电池反应可形成可逆振荡.由表面活性剂对电极表面的吸附和乳液结构变化解释了振荡机理.乳液混合能参与了此电化学反应.     

表面活性剂胶束对MA-AA复合振荡反应的影响

化学振荡反应是一类典型的非线性现象[1-5],研究各种因素对化学振荡反应的动力学控制问题在生物和化学应用中有重要的意义[6,7].生物体系中化学振荡反应实际上是产生于溶胶中(包括高分子溶液和表面活性剂溶液)[8],因此,要模拟生物体系的化学振荡就不能不考虑溶胶对振荡反应的影响.     

单晶表面上水-气转移反应动力学及可逆吸附的作用—─Monte Carlo 模拟研究

用二元方格网络表示Ｃｕ（１１１）单晶表面上吸附活性位构型，建立了一个水－气转移反应的蒙特卡罗模型；对水－气转移反应的动力学进行了模拟，并研究了可逆吸附在表面反应中的重要作用．当水的解离吸附为反应的决速步骤时，模拟得到的ＣＯ和Ｈ２Ｏ的反应级数与Ｃａｍｐｂｅｌ等的单晶实验结果一致．模拟研究还表明，可逆吸附不仅可以抑制催化剂表面同种吸附物种ｃｌｕｓｔｅｒ的形成，而且可以不断提供新的吸附活性位，从而使表面反应稳定进行得以维持．     

新型液膜振荡器

表面活性剂不仅对均相的非线性化学反应动力学研究有重要作用”－‘］,而且表面活性剂穿越油水界面扩散时形成的自发液膜振荡过程亦可作为一个简单模型,用以说明多相反应与扩散偶合所产生的复杂周期现象,特别是说明生物系统生理现象中的振荡与混饨．这些早在贺占博的博士论文l’］就已提出,但至今此方面的研究仍进展甚微,而其意义却非常重大,迫切需要进一步研究．关于液膜振荡的本质,目前有两种说法．一种是界面流体力学的Marangoni效应,另一种为化学本质的胶束一单分子膜一反胶束的表面活性剂聚集状态的周期变化l’‘．我们的实验…     

SCN——BrO3——H+体系的非线性动力学行为

＄酸盐驱动的振荡器，特别是Belousov－Zhabotinskii反应［‘1及其变种是研究得最为广泛、最为透彻的均相化学振荡反应．但两组份非催化的漠酸盐振荡器还只是近年来才发现开始研究的·含硫化合物如SC（NH。）。，SO3－，SCN一等非催化滇酸盐振荡器的非线性行为逐渐成为研究热点     

N2O分解反应中复杂动力学行为的模拟

在多相催化反应中，自ZO多年前第一次在实验中观察到反应的振荡现象以来，现已发现在许多催化反应中都存在振荡现象山．N。O分解是一个振荡反应问．我们在用MonteCarloMC）方法研究N20分解反应机理时，曾发现反应速率和表面覆盖度在一定条件下都会出现振荡现象＊．非统性理论的研究表明，体系内部只要存在非线性的相互作用就可能表现出一些复杂的动力学行为，如振荡和混饨等．N。O分解反应中的振荡行为，也是由于体系内部非线性相互作用的结果·本文用非线性动力学的方法研究N。O分解反应中表面氧覆盖度的振荡行为，发现振荡在一定条…     

表面活性剂增敏动力学光度法测定钯

１ 引 言 动力学光度法测定钯已有报道 所用体系主要有两种类型，一种是利用钯催化次磷酸钠还原有色试剂的反应，另一类型是钯的催化氧化反应。近年来，表面活性剂在动力学分析中的应用日益受到重视。它可提高分析的灵敏度和选择性，改善反应条件，简化分析手续等；作者研究发现，钯对高碘酸钾氧化结晶紫（ＣＶ））褪色有催化作用，体系中加入ＳＤＢＳ后，体系的最大吸收波长紫移，测定的灵敏度明显提高，据此建立了测定钯的动力学光度法。２ 实验方法 取两支 １０ｍｌ具塞比色管，于其中一支加入适量钯标准溶液，再分别在两支管中依次加入 …     

光敏型季铵盐类阳离子表面活性剂的合成及表面活性和泡沫性质

本文报道了一种光敏型的阳离子表面活性剂（AZO），其分子结构中含有偶氮苯基团，并研究了光照对表面活性和泡沫性能的影响。经紫外光照射后，表面活性剂的饱和吸附量（Г_max）减小，临界胶束浓度（cmc）、最低表面张力（γ_cmc）和分子极限占有面积（A_min）增大；气泡数目增多，直径变小，发泡能力和泡沫稳定性降低。实验结果证实，该表面活性剂的表面活性和泡沫稳定性可以用光照进行调控。     

乳液引发的电化学振荡

丹尼尔电池;可逆;蓄电池;乳液引发的电化学振荡     

Oscillations Produced From Acidity Hydrolysis of Triglyceride in Emulsion

A new type of oscillating reaction was found from the systematic design of the chemical oscillator in water in oil (W/O) emulsions. It is an acidity hydrolysis reaction of long chain triglyceride in W/O emulsion at 25.0 ± 0.1°C in a bath stirring reactor. During the process of reaction, there were periodic and semi‐periodic changes lasting more than 10 hours both in electrolytic conductivity and electric potential. Microscope also revealed that the emulsion structure changed regularly and quickly. Because of the large difference in the solubility of the hydrolyzed products, it could be thought, that the different redistribution in the two phases of water and oil induces the regular changes. Marangoni effect of interface membrane made oscillation to form. The oscillating reaction can be used to explain the periodic change in the living system produced from coupling between reaction and diffusion.     

Elementary reactions of the emulsions polymerization of styrene with the localization of radical formation acts at the interface

The localization of radical formation acts at the interface achieved by the application of specially prepared surfactant initiators, fixation of initiating sites on the surface of seed latex particles by covalent bonds, or by redox initiating systems were experimentally studies. It is ascertained that the fixation of the initiator of polymerization at the interface of the emulsion system brings about a change of the kinetic parameters of its decomposition—an increase in the decomposition rate and decrease in the initiation efficiency. The experiments (measurements of chain propagation rate) demonstrated that the nature of emulsifying agent and initiator has no effect on the chain propagation acts. The kinetics of the chain termination depends on the properties of the emulsion system that is revealed in the dependence of chain termination constants on the type of initiator and the diameter of latex particles. These effects are supposed to be explained by influence of the colloid and chemical parameters of the reaction system on the conformation entropy of the growing macroradicals; and the low values of the chain termination constants (10²–10⁴ L mol^?1 s^?1) are due to the higher activation energy of chain termination for the emulsion polymerization.     

Preparation of PEG-modified urethane acrylate emulsion and its emulsion polymerization

In order to improve stability and reduce droplet size, the PEG-modified urethane acrylates were synthesized by the reaction of polyethylene glycol (PEG) with residual isocyanate groups of urethane acrylate to incorporate hydrophilic groups into the molecular ends. The droplet sizes of the PEG-modified urethane acrylate emulsions were much smaller than those of unmodified urethane acrylate emulsions at the same surfactant composition, and the droplet sizes of these emulsions were significantly effected not by surfactant compositions and types, but by the reaction molar ratio of PEG, because the urethane acrylate containing polyoxyethylene groups as terminal groups aided the interfacial activity of surfactant molecules and acted as a polymeric surfactant. The actions of PEG-modified urethane acrylate were confirmed by the investigation of adsorption of urethane acrylate in a water/benzene interface.For polymerization of emulsions, the stability of emulsion in the process of emulsion polymerization was changed by the type of surfactant or initiator. In the case of emulsion polymerization with a water soluble initiator (K₂S₂O₈), the emulsions prepared using TWEEN 60 were broken in the process of polymerization. However, polymerization of these emulsions could be carried out using an oil soluble initiator (AIBN). The conversion of emulsion polymerization changed with the type of urethane acrylates, that is, the reaction molar ratio of PEG to 2-HEMA.     

Preparation and properties of thermo-sensitive organic/inorganic hybrid microgels

By utilizing the hydrolysis and condensation of the methoxysilyl groups, thermo-sensitive organic/inorganic hybrid poly[ N-isopropylacrylamide- co-3-(trimethoxysilyl)propylmethacrylate] [P(NIPAm- co-TMSPMA)] microgels were successfully prepared via two different methods without addition of any surfactant. First, the microgels were obtained by a two-step method; that is, the linear copolymer P(NIPAm- co-TMSPMA) was first synthesized by free radical copolymerization, and the aqueous solution of the copolymer was then heated above its low critical solution temperature (LCST) to give colloid particles, which were subsequently cross-linked via the hydrolysis and condensation of the methoxysilyl groups to form the microgels. Second, the microgels were also prepared via conventional surfactant-free emulsion polymerization (SFEP) of the monomers NIPAm and TMSPMA. TMSPMA can act as the cross-linkable monomer. No surfactant was involved in the preparation of the hybrid microgels. The obtained microgels were rather spherical and exhibited reversible thermo-sensitive behavior. The size, morphology, swellability, and phase transition behavior of the microgels were dependent on the initial copolymer or monomer concentration, preparation temperature, and the content of TMSPMA. The size of microgels obtained by SFEP was found to be more uniform than that by the two-step method. The hybrid microgels obtained by these two methods had more homogeneous microstructures than those prepared via conventional emulsion polymerization with chemical cross-linker N, N'-methylene-bisacrylamide.     

Further insight into the mechanism of poly(styrene‐co‐methyl methacrylate) microsphere formation

Polymeric microspheres have been used in a broad range of applications from chromatographic separation techniques to analysis of air flow over aerodynamic surfaces. The preparation of microspheres from many polymer families has consequently been extensively studied using a variety of synthetic approaches. Although there are a myriad of polymeric microsphere synthesis methods, free‐radical initiated emulsion polymerization is one of the most common techniques. In this work, poly(styrene‐co‐methyl methacrylate) microspheres were synthesized via surfactant‐free emulsion polymerization. The effects of co‐monomer composition and addition time on particle size distribution, particle formation, and particle morphology were investigated. Particles were characterized using dynamic light scattering and scanning electron microscopy to gain further insight into particle size and size distributions. Reaction kinetics were analyzed through consideration of characterization results. A particle formation mechanism for poly(styrene‐co‐methyl methacrylate) microspheres was proposed based on characterization results and known reaction kinetics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2249–2259     

Charge Density Overcomes Steric Hindrance of Ferrocene Surfactant in Switchable Oil-in-Dispersion Emulsions

A ferrocene surfactant can be switched between single and double head form (FcN⁺C₁₂/Fc⁺N⁺C₁₂) triggered by redox reaction. FcN⁺C₁₂ can neither stabilize an O/W emulsion alone nor an oil-in-dispersion emulsion in combination with alumina nanoparticles due to the steric hindrance of the ferrocene group. However, such steric hindrance can be overcome by increasing the charge density in Fc⁺N⁺C₁₂, so that oil-in-dispersion emulsions can be co-stabilized by Fc⁺N⁺C₁₂ and alumina nanoparticles at very low concentrations (1×10⁻⁷ M (≈50 ppb) and 0.001 wt %, respectively). Not only can reversible formation/destabilization of oil-in-dispersion emulsions be achieved by redox reaction, but also reversible transformation between oil-in-dispersion emulsions and Pickering emulsions can be obtained through reversing the charge of alumina particles by adjusting the pH. The results provide a new protocol for the design of surfactants for stabilization of smart oil-in-dispersion emulsions.     

Benzylmalonic acid reaction with iodine and behavior in a Briggs–Rauscher oscillator

Benzylmalonic acid (BzMA) reacts via an enol mechanism with aqueous iodine to form rather stable iodobenzylmalonic acid. In the presence of iodate, which oxidizes iodide to di‐iodine, the reaction goes to completion. The kinetics of the reaction BzMA + I₂ + IO₃^? + H⁺ have been studied and the results were interpreted with a suitable mechanism. In a mixture with acidic iodate, hydrogen peroxide, and manganous ions, BzMA can serve as a substrate for a Briggs–Rauscher‐type oscillating reaction. The behavior of this oscillator has been studied in detail. A mechanistic interpretation of the oscillations based on a new kinetic model is also given. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 357–365, 2002     

乳液变化中的pH与电导率振荡

A series of oscillators of pH and conductivity in emulsion structure change were found from composition change and component substitution of triglyceride hydrolysis oscillator which had been discovered by the author.The experimental results show that without any chemical reaction there are still various oscillations in the inner diffusion of the emulsion. During the oscillatory process, periodic change of interface membrane in the emulsion could be obseved by a 100× microscope. The oscillation phenomena have been briefly explained by Marangoni effect due to component substitution.