聚羧酸盐分散剂在农药水悬浮剂中的应用及作用机理分析

聚羧酸盐分散剂具有独特的分散性能,可显著提高农药水悬浮剂等剂型的稳定性.本文应用3种聚羧酸盐分散剂分别制备了3种农药水悬浮剂,研究了聚羧酸盐分散剂在原药颗粒表面的吸附特征和吸附热力学,研究了聚羧酸盐分散剂对农药水悬浮体系Zeta电势和流变性质的影响,并分析了体系在热贮前后各稳定性参数的变化,最终得到了具有长期储存稳定性的农药水悬浮剂产品.研究结果显示,聚羧酸盐分散剂在原药颗粒表面的吸附符合Langmuir单分子层吸附模型,其中吸附热力学参数?G_(ad)0、?S_(ad)0、?H_(ad)0且|?H_(ad)|40 kJ mol~(-1),表明该吸附为自发进行的、放热、熵增的物理吸附过程.聚羧酸盐分散剂通过提高悬浮体系的Zeta电势,使得分散粒子间相互排斥,改善了体系的流动性能,从而提高农药水悬浮剂产品的长期储存稳定性.     

十二醇聚氧乙烯醚的表面性能及在水悬浮剂中的应用

探讨了十二醇聚氧乙烯醚(AEO)的EO链长对其临界胶束浓度(cmc)、表面张力(γcmc)、胶束生成自由能(ΔGm)、分子面积(Acmc)和亲水亲油平衡(HLB)值等表面性能的影响;同时研究了不同EO链长的AEO对质量分数25%代森锰锌水悬浮剂(SC)的流变性能[黏度、储能模量(G’)、流动点时的应变(γflow)、触变性]和物理贮存性能(热贮前悬浮率、热贮后悬浮率和倾倒性)的影响.结果发现,AEO的cmc,γcmc,ΔGm,Acmc和HLB值随着EO链长的增加而增大;AEO能够明显改善代森锰锌SC的黏度,以AEO-9所制备的SC黏度最小,且AEO的EO链长越长,所对应的SC结构恢复越慢,恢复慢的样品其倾倒残留率过高;G’和γflow能反映SC内部结构变化,可作为评价农药SC物理稳定性流变学指标.     

壬基酚聚氧乙烯醚二聚和三聚表面活性剂的合成及表面性质

合成了系列壬基酚聚氧乙烯醚二聚表面活性剂(DNP)和三聚表面活性剂(TNP), 用核磁共振、红外光谱和元素分析等手段对其结构进行了表征, 并用表面张力法和稳态荧光法对DNP和TNP的表面性能进行了研究. 结果表明, 随着氧乙烯(EO)单元数的增长, DNP和TNP的临界胶束浓度(cmc)值逐渐增大; DNP和TNP的cmc值较相应的单体壬基酚聚氧乙烯醚表面活性剂(NP)明显降低, 显示了较高的表面活性、吸附能力和润湿能力.     

聚丙烯酰胺/聚L-谷氨酸苄酯接枝共聚物的合成及其胶束制备

以聚丙烯酰胺(PAM)为大分子引发剂, 采用开环聚合方法, 在N,N-二甲基甲酰胺(DMF)中引发L-谷氨酸苄酯环内酸酐(BLG-NCA)聚合合成了两亲性聚丙烯酰胺/聚L-谷氨酸苄酯接枝共聚物(PAM-g-BLG), 采用IR, 1H NMR和GPC方法对共聚物结构进行了表征; 用芘作荧光探针, 研究了共聚物胶束的形成及其临界胶束浓度(cmc), 利用动态光散射(DLS)和透射电镜(TEM)研究了胶束的粒径分布和形态. 结果表明, PAM能够引发BLG-NCA开环聚合得到接枝共聚物, 在一定条件下接枝共聚物能够形成球形的稳定胶束, cmc值和胶束粒径随着共聚物中疏水性聚L-谷氨酸苄酯(PBLG)链段含量的增加而减小.     

原位凝聚法制备聚电解质微胶囊——模板中掺杂聚电解质量对微胶囊结构与性能的影响

通过在CaCO3制备过程中加入不同浓度聚苯乙烯磺酸钠(PSS)的方法来控制掺杂进CaCO3粒子中的PSS含量,得到了PSS掺杂量为4%～11%,尺寸均匀的CaCO3球形微粒.在微粒表面仅吸附一层聚烯丙基胺盐酸盐(PAH)后,用乙二胺四乙酸二钠(EDTA)使碳酸钙溶解;释放出的PSS与PAH原位凝聚制备得到了分散良好且完整的聚电解质复合物微胶囊.在所研究的范围内,模板微粒中PSS的含量对微胶囊的形态结构和性能没有明显影响.与传统的层层组装微胶囊相比,聚电解质复合物微胶囊有较好的热稳定性,但在高盐浓度下尺寸收缩程度较大.由于和层层组装微胶囊相比缺乏结合紧密的有序结构,原位凝聚法制备的微胶囊囊壁的截留分子量较大.     

烷基聚葡糖苷溶液的表面吸附平衡与动力学

用吊片法和气泡最大压力法分别测定了烷基聚葡糖苷(APG)C₉.₆G_1.3水溶液的平衡和动态表面张力,研究了APG水溶液表面的吸附平衡、动力学及其影响因素.测得其cmc(临界胶束浓度)为0.032g/L.吸附过程由初始的扩散控制转变到势垒控制,吸附势垒为4～7kJ/mol.温度升高,平衡和动态表面张力均减小,吸附量增加;加入无机盐,平衡和动态表面张力增大,吸附量亦增加;醇类的吸附使动态表面张力下降速率加快,表明APG与醇分子间有协同吸附作用.     

全氟壬烯氧基苯磺酸钠与四丁基溴化铵的相互作用

通过全氟壬烯氧基苯磺酸钠(C9F17OC6H4SO3Na,OBS)与四丁基溴化铵(TBAB)的复配,研究了OBS与TBAB复配体系的表面性能和润湿性能。在不同摩尔比下碳氟表面活性剂与季铵盐复配体系的临界胶束浓度(cmc)、最低表面张力(γcmc)、复配体系的总饱和吸附量(Γtm)和极限分子面积(Amin)的研究结果表明,在最佳等摩尔比时,体系的cmc和γcmc被降到最低,获得了最大总饱和吸附量(Γtm)(5.27 mol.cm-2)和最小的极限分子面积(Amin)(0.32 nm2),使其在水溶液中的表面性能增强。同时等摩尔比的复配体系,在大于0.10mmol.L-1的浓度区复配体系接触角较小,显示比较好的润湿性。     

具有乙二醇侧链的聚谷氨酸酯的合成、表征及其两亲性

聚氨基酸具有良好的生物相容性和规整二级结构, 可作为生物医学材料应用. 如果聚氨基酸具有两亲性, 则能够形成纳米尺寸的胶束结构, 有望作为生物降解药物释放载体. 为得到两亲性的聚谷氨酸, 通过小分子开环聚合的方法直接制备了具有乙二醇侧链的聚谷氨酸酯. 首先制备了γ-(2-(甲氧基)乙基)-L-谷氨酸酯和γ-(2-(2-甲氧基乙氧基)乙基)-L-谷氨酸酯, 然后与三聚光气反应得到其N-羧酸酐(NCA). N-羧酸酐(NCA)单体经开环聚合反应合成了具有乙二醇侧链的聚谷氨酸酯(PEG_nG). 利用IR, ¹H NMR, GPC和吸湿性测定等方法对所合成聚合物进行了详细的表征. 结果表明随着侧链中EG含量的提高, 聚L-谷氨酸酯的亲水性有明显改善. 透射电镜的结果表明, 聚谷氨酸二乙二醇单甲醚酯(PEG₂G)在水溶液中能够形成稳定胶束结构.     

支链异构十五烷基间二甲苯磺酸钠溶液表面性质及其溶剂行为

合成了4种高纯度十五烷基间二甲苯磺酸钠,测定了在纯水溶液和0.039 3 mol/L异丙醇溶液中的表面性质. 结果表明,随芳基向碳链中间位置的移动,临界胶束浓度(cmc)增大,分子极限占有面积(Amin)增大,标准吸附自由能(ΔG0)变得更负,降低表面张力的效率(pc20)增强,饱和吸附量(Γmax)降低,临界胶束浓度时的表面张力(γcmc)降低,异丙醇使磺酸钠溶液的cmc显著降低. 从分子结构的特点探讨了分子中脂肪链支化程度对其表面性能的影响.     

交联聚天冬氨酸基聚离子胶束的制备与表征

通过胺端基聚乙二醇(CH3O-PEG-NH2)开环聚琥珀酰亚胺(PSI), 进一步碱解和胺解制备了聚乙二醇接枝聚天冬氨酸(PEG-g-PAsp)和聚乙二醇接枝聚乙二胺基天冬酰胺(PEG-g-PDEA)两种聚天冬氨酸衍生物. 利用它们之间的静电相互作用, 在磷酸缓冲液中形成了以PEG为壳、聚天冬氨酸复合物为核的聚离子胶束. 研究发现, 该聚离子胶束粒子呈球形, 粒径约为70 nm, 且粒径分布较窄. 然而, 体系的稳定性受溶液的pH和盐离子强度影响较大. 通过戊二醛交联PEG-g-PDEA中的伯胺可以有效提高该聚离子胶束对pH和盐离子强度的稳定性.     

十五烷基芳基磺酸钠溶液表面性质的影响因素研究

测定了自制的四种高纯度十五烷基间二甲苯磺酸钠在纯水溶液和0.0393 mol/L异丙醇溶液中的表面性质,结果表明,随芳基向碳链中间位置的移动,临界胶束浓度cmc增大,分子极限占有面积Amin增大,标准吸附自由能 变得更负,降低表面张力的效率pc20增强,饱和吸附量Γ_max降低,临界胶束浓度时的表面张力γ_cmc降低;且异丙醇的加入使磺酸钠溶液的临界胶束浓度显著降低。从分子结构的特点探讨了分子支化程度对表面性能的影响。     

Chemical potential of a nonionic surfactant in solution

The chemical potential of a surfactant in solution can be calculated from the Gibbs adsorption equation when the surface excess of the surfactant and the surface tension of the solution as a function of surfactant concentration are known. We have investigated a solution of the nonionic surfactant 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in the polar solvent 3-hydroxypropionitrile at concentrations below and above the critical micelle concentration (cmc). Neutral impact collision ion scattering spectroscopy was applied for the direct measurement of the surface excess of POPC as a function of concentration. The Gibbs adsorption equation was applied in conjunction with surface tension measurements to evaluate the chemical potential and the activity coefficients of POPC, respectively. We find that the solution shows ideal behavior up to the cmc and that the chemical potential remains constant at concentrations larger than the cmc.     

Self-assembly and micellization of amphiphilic rod-coil block oligomer at the mica-water interface

In this paper, in situ atomic force microscopy has been used to investigate the micellization and self-assembling structure of an amphiphilic rod-coil block oligomer (EO16OPV) containing a conjugated oligo(phenylene vinylene) dimer and poly(ethylene oxide) at the mica-water interface. It is found that EO16OPV molecules have strong adsorption and aggregation properties on mica. In the wide concentration range from above the critical micelle concentration (cmc) to far below the cmc, a closely packed layer of stripe-like micelles with two preferred orientations can be formed at the mica-water interface. A cylindrical micelle structure for the stripes is proposed. We demonstrate that the stripe-like micelles formed on mica originate from different micellization processes at solution concentrations above and below the cmc. The origins of the strong micellization properties and oriented arrangement of the stripes are also discussed.     

乙醇/水混合溶剂中Gemini表面活性剂的表面性质

通过对Gemini表面活性剂12-s-12 (Et)(s=4, 6, 8, 10, 12)体系在乙醇/水混合溶剂中的表面张力曲线的测定, 对该体系的表面性质进行了研究. 发现随乙醇/水比例变化, Gemini各种表面化学性质, 如临界胶束浓度(cmc)、表面张力(γcmc)、饱和吸附量(Γmax)和最小分子占有面积(Amin)等的变化规律. 拓展了Gemini表面活性剂在混合溶剂中表面吸附的研究.     

全氟丁基磺酸钠与辛基三乙基溴化铵的相互作用

通过测定辛基三乙基溴化铵(C8H17N(CH2CH3)3Br,C8NE)与全氟丁基磺酸钠(C4F9SO3Na,C4F)组成的不同混合比的碳氢-碳氟正负离子表面活性剂混合体系的表面张力,得到不同摩尔比时C8NEC4F体系的临界胶束浓度(cmc)、cmc处的表面张力(γcmc)、总饱和吸附量、不同表面张力时表面吸附层的组成,利用Gibbs-Duhem方程求得cmc处的胶团组成。 采用规则溶液理论计算了胶团中分子间相互作用参数(βm),并求得cmc以上的胶团组成。 实验表明,C8NEC4F复配体系的cmc远远小于单体系的cmc,这也体现在该体系的βm负值很大,胶团内分子相互作用很强。 但是C4F与C8NE复配后γcmc较C4F单体系的变化幅度不是特别大(γcmc降低2~4 mN/m),这是由于C8NEC4F碳链的不对称性导致部分C8NE的碳链在溶液表面弯曲而覆盖了C4F端基CF3基团。 表面吸附层中氟表面活性剂相对于本体溶液是富集的,即使对于C8NE大大过量的体系,表面吸附层组成也在等摩尔附近;对于C4F过量的体系,C4F在表面吸附层中的比例比溶液中的略高。 随着表面张力的降低,表面吸附层的组成相对更偏向于氟表面活性剂。 cmc处的胶团组成随着体系中C4F含量的增大偏向于形成显著富含C4F的胶团,对于C8NE大大过量的体系,胶团组成接近等摩尔。 cmc之后的胶团组成接近等摩尔,主要归因于此时静电相互作用占主导,这和溶液配制过程中发现复配体系超过cmc一定浓度后就易生成沉淀的现象是相符的。     

pH-responsive diblock copolymer micelles at the silica/aqueous solution interface: Adsorption kinetics and equilibrium studies

The adsorption behavior of two examples of a weakly basic diblock copolymer, poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2-(diethylamino)ethyl methacrylate) (PDMA-PDEA), at the silica/aqueous solution interface has been investigated using a quartz crystal microbalance with dissipation monitoring and an optical reflectometer. Dynamic and static light scattering measurements have also been carried out to assess aqueous solution properties of such pH-responsive copolymers. In alkaline solution, core-shell micelles are formed above the critical micelle concentration (cmc) by both copolymers, whereas the chains are molecularly dissolved (as unimers) at all concentrations in acidic solution. As a result, the adsorption behavior of PDMA-PDEA diblock copolymers on silica is strongly dependent on both the copolymer concentration and the solution pH. Below the cmc at pH 9, the cationic PDMA-PDEA copolymers adsorb as unimers and the conformation of the adsorbed polymer is essentially flat. At concentrations just above the cmc, the initial adsorption of copolymer onto the silica is dominated by the unimers due to their faster diffusion compared to the much larger micelles. Rearrangement of the adsorbed unimers and/or their subsequent displacement by micelles from solution is then observed during an equilibration period, and the final adsorbed mass is greater than that observed below the cmc. At concentrations well above the cmc, the much higher proportion of micelles in solution facilitates more effective competition for the surface at all stages of the adsorption process and no replacement of initially adsorbed unimers by micelles is evident. However, the adsorbed layer undergoes gradual rearrangement after initial adsorption. This relaxation is believed to result from a combination of further copolymer adsorption and swelling of the adsorbed layer.     

甲酰胺与正负离子表面活性剂有序溶液的研究

对羧酸钠与烷基三甲基溴化铵1：1混合体系的研究表明：常温下各体系在不同比例甲酰胺（FA）／水混合溶剂中，表面张力随浓度变化均有明显的转折点，显示了混合体系中胶团的存在．实验中发现随混合溶剂中FA比例增加，各体系的临界胶团浓度（cmc）增大．在较高温度下发现在甲酰胺中亦存在着因胶团形成而产生的表面张力-浓度对数（γ－logc）曲线的转折点，利用相分离模型对体系胶团热力学参数进行了计算．并探讨了FA对正负离子表面活性剂囊泡的影响．     

酰胺基团对Gemini表面活性剂表面活性和聚集行为的影响

本文合成了含酰胺基团和不含酰胺基团的两类Gemini阳离子表面活性剂,测定了其表面活性参数,研究了酰胺基团对表面活性剂的表面活性和聚集行为的影响。结果表明,酰胺基团提高了Gemini阳离子表面活性剂的临界胶团浓度,降低了胶团聚集数,增强了胶团微极性,增大了表面活性剂的饱和吸附量。     

多烷基苯磺酸钠水溶液的表面性质

研究了多烷基苯磺酸钠的结构, 特别是侧链碳原子数的增加, 对其表面活性的影响, 并与其它烷基苯磺酸钠进行了比较. 结果表明, 随着苯环上侧链碳原子数的增加, 多烷基苯磺酸钠的临界胶束浓度(cmc)降低, 但侧链上CH2降低cmc的程度远小于主链上CH2的作用. 当侧链碳原子数增加时, 多烷基苯磺酸钠的饱和吸附量(Γmax)降低, 表现出与主链不同的变化规律. 从多烷基苯磺酸钠的结构解释了cmc和Γmax的变化规律.     

Synthesis and surface properties of anionic gemini surfactants with amide groups

Novel anionic gemini surfactants, 1,2-bis(N-beta-carboxypropanoyl-N-alkylamino)ethane (2CnenAm; n is hydrocarbon chain length of 6, 8, 10, 12, or 14), with two hydrocarbon chains, two carboxylate groups, and two amide groups, were synthesized by three-step reactions. Their solution properties were characterized by equilibrium and dynamic surface tension, steady-state fluorescence spectroscopy of pyrene, and dynamic light-scattering techniques. The surface tension measurements of 2CnenAm give low critical micelle concentrations (cmc), great efficiency in lowering the surface tension, and strong adsorption at air/water interface. Gemini surfactants behave normally with the logarithm of cmc decrease linearly with the chain length. In addition, adsorption and micellization behavior of 2CnenAm was estimated by parameter of pC20, cmc/C20, and standard free energy (DeltaG(0)mic and DeltaG(0)ads); they are significantly influenced by hydrocarbon chain length, and the adsorption is promoted more than the micellization as chain length becomes longer. The results of dynamic light-scattering and fluorescence quenching indicate that small micelles of 2CnenAm are observed at the concentrations above the cmc, and further large particles are also seen. Further, from the dynamic surface tension measurements, it is found that the shorter hydrocarbon chain length of 2CnenAm, the faster the rate of decrease of surface tension.