【作者】 白燕；

【导师】 徐桂英； 郝爱友；

【作者基本信息】 山东大学 ， 物理化学， 2009， 博士

【摘要】 环糊精—表面活性剂复配体系不仅在药物、化妆品、生物及食品等领域中有着广泛的应用,而且还可用于模拟生物体系,对加快生物技术向化工、医药等传统领域的渗透和应用具有重要的意义。所以环糊精和表面活性剂相互作用的研究是多年来人们一直十分感兴趣的研究课题。关于环糊精与表面活性剂相互作用的研究报道有很多,如烷基三甲基溴化铵（CnTAB）、SDS和Triton X-100等与环糊精的相互作用。表面活性剂特别是离子型表面活性剂在溶液中的性质受添加剂如无机盐和极性有机物的影响。CnTAB是一类传统阳离子型表面活性剂,无机盐的加入对其水溶液的性质有较大的影响,也必将影响到其与环糊精的相互作用。改性环糊精具有较为独特的性质,修饰基团的链长、取代位置、取代度对它们与表面活性剂的相互作用也有影响。本文主要研究了NaBr对CTAB和TTAB与β-CD的相互作用的影响,并与NaCl的作用进行了比较;研究了四种改性环糊精与TTAB、CTAB的相互作用;考查了烷基三甲基溴化铵通过化学修饰接到环糊精上的改性环糊精2-O-（羟丙基-N,N-二甲基-N-十二烷基铵）-β-环糊精水溶液的性质;研究了改性环糊精对碳纳米管（CNTs）的分散作用以及CnTAB与β-CD的相互作用对CnTAB分散CNTs作用的影响,环糊精对碳酸钙在体相和界面上的结晶过程的影响,研究内容共分为五部分:论文的第一部分概述了表面活性剂和环糊精相互作用的重要意义,综述了表面活性剂和环糊精相互作用的研究进展。论文的第二部分可分为三小节。第一节用表面张力法和界面扩张流变法研究了CTAB和β-CD的相互作用,发现其表面张力等温线有两个拐点,比较了NaBr和NaCl对其相互作用的影响。共同点有:体系中都存在1:1和1:2两种CTAB/β-CD复合物,1:1型复合物参与界面吸附;可以降低复合体系的cmc^*,增大复合体系的吸附效率,并且NaBr的效率更高;包结计量比R随加入的盐浓度的增大,先降低后升高,说明1:2型复合物的含量先降低后升高。CTAB的扩张模量随频率的增加而增加,加入电解质,扩张模量有所降低;扩张模量随β-CD浓度的增大,先增大后降低,并且在β-CD浓度较高时,扩张模量随频率的升高而降低,与纯CTAB体系的规律相反。NaBr和NaCl可以降低CTAB、CTAB/β-CD复合体系的扩张模量,但要降低到相同的程度所需的NaCl的浓度大于NaBr的浓度。第二节通过对表面张力等温线的分析,可得到NaBr对TTAB、CTAB与β-CD相互作用的影响,从而得到表面活性剂疏水链长的影响。β-CD的存在时,CTAB的吸附效率依然高于TTAB,同时cmc^*和cmc/c₂₀的数值小于TTAB,这表明CTAB的表面活性大于TTAB,且更容易形成胶束。NaBr对CnTAB/β-CD体系的γ_cmc的影响主要是两个因素竞争的结果:第一,加入NaBr压缩离子头基双电层,因头基与β-CD间的离子—偶极作用,CnTAB离子头基与环糊精大环之间的CnTAB的主链上原来不在空腔中的亚甲基被缩进空腔中,但空腔能容纳的亚甲基数目一定,所以相应数目的亚甲基被挤出β-CD另一端,复合物的有效疏水链长增长,有利于复合物在界面上的吸附;第二,加入NaBr降低CnTAB的电离度,压缩头基双电层,CnTAB在界面上的排列更为紧密,复合物在界面上吸附的量降低,对γ_cmc的影响减小。第三节通过表面张力法研究了四种短链改性环糊精（2-HP-β-CD、6-HP-β-CD、2-HB-β-CD、6-HB-β-CD）和TTAB、CTAB在水溶液中的相互作用。比较了取代基链长、取代度、取代位置的差异;并与TX-100与改性环糊精的作用进行了对比。改性环糊精本身有一定的表面活性,其水溶液的表面张力随浓度的增大而降低。CnTAB/CD混合溶液的表面张力等温线在第一个拐点前的表面张力随改性环糊精浓度的增大而降低,随CTAB浓度的增大而缓慢下降,说明这时CTAB/2-HP-β-CD复合物也吸附在界面上,且表面活性与2-HP-β-CD相似。改性环糊精本身具有表面活性,取代基链长的作用最大,其次是取代度和取代位置:链长越长,取代度越大,表面活性越大,并且6位取代的环糊精的表面活性大于2位取代的环糊精的表面活性。对于改性环糊精和CnTAB混合体系而言,包结计量比R与取代位置有关:2位取代CD与β-CD相同,都是1:1型复合物为主;而在6位取代的CD的复合物则是2:1型复合物为主。2位取代CD的cmc^*大于6位取代CD的cmc^*;6位取代CD以及β-CD与CnTAB形成的1:1型复合物降低γ_cmc的能力大于2位取代的CD。CTAB体系比TTAB体系更容易与CD形成2:1型复合物;在CD/CnTAB混合体系中,CTAB降低表面张力的效率优于TTAB。在β-CD和6-HP-β-CD中,CTAB降低表面张力的能力不如TTAB,而在2-HP-β-CD、6-HB-β-CD、2-HB-β-CD中,CTAB降低表面张力的能力与TTAB一样。CTAB/2-HP-β-CD的γ_cmc随CD浓度的增大缓慢下降到平台,而TX-100/2-HP-β-CD体系的γ_cmc与CD浓度无关,证实了CTAB/CD的γ_cmc降低是因为复合物参与到表面活性剂的界面吸附层中。圆二色光谱研究TX-100与CD的混合溶液,发现混合体系的诱导手性源于苯环与CD空腔中的氢键环的作用,氢键环越强,诱导手性越强,β-CD以及氢键环破坏较小的6位取代CD有诱导手性,而2位取代CD的氢键环破坏严重,没有诱导手性出现。论文的第三部分共分为两节来讨论。第一节主要通过UV-vis-NIR吸收光谱、拉曼光谱、FTIR、XRD和TGA等方法研究了β-CD及其四种衍生物分散CNTs的能力,比较了分子结构对CNTs分散能力的影响。CD对CNTs的分散性可能是取代基类型、链长、位置以及取代度综合作用的结果,2-HB-β-CD的分散效果最好。CD浓度较高时,出现不利于CNTs分散的聚集体导致CNTs的聚沉,分散能力下降。CD对CNTs的分散作用主要靠CD和CNTs间的弱范德华力以及吸附在CNTs表面的CD的分子间氢键。第二节通过UV-vis-NIR吸收光谱、拉曼光谱等方法研究了CnTAB与β-CD相互作用对CnTAB分散CNTs的能力的影响,谈论了表面活性剂烷基链长、浓度和β-CD浓度的影响。对CnTAB/CNTs体系来说,烷基链长对分散CNTs的影响很大,DTAB分散的CNTs量最小,TTAB和CTAB分散的量大幅度增大,且两者的最大分散量相似,但达到相同分散量所需CTAB浓度较TTAB小。在cmc之前,DTAB溶液没有分散CNTs的能力,而TTAB和CTAB则可以分散CNTs。体系中加入β-CD后,三种CnTAB都在cmc^*之前具有了分散CNTs的能力,疏水链越长,分散能力越大。β-CD聚集体的形态对复合体系分散CNTs的影响很大,β-CD单体与CnTAB形成的复合物的分散能力最好,其它聚集体因为桥连作用反而降低了CNTs的分散量。β-CD复合物能吸附在CnTAB分散开的CNTs上,增强分散体系的稳定性;β-CD较大的聚集体与少量CnTAB作用后,具有一定分散CNTs的能力。CnTAB/β-CD/CNTs分散的体系的稳定性主要靠离子头基的静电斥力和β-CD单体及聚集体的空间位阻作用。论文的第四部分采用表面张力、电导、界面膨胀流变等方法研究了新型两性环糊精——2-O-（羟丙基-N,N-二甲基-N-十二烷基铵）-β-环糊精(HPDMA-C₁₂-CD)在水溶液中的聚集行为并考察了温度的影响。HPDMA-C₁₂-CD及其自包结复合物都可以在界面上吸附并有效降低水的表面张力,而在DTAB/β-CD、DTAB/2-HP-β-CD体系中,主要是靠DTAB的吸附来降低表面张力,复合物的作用较小;从HPDMA-C₁₂-CD表面张力等温线上可以得到明显的cmc拐点。在15-50℃之间,温度对HPDMA-C₁₂-CD的胶束尺寸没有影响。HPDMA-C₁₂-CD的胶束化过程在低温时为熵驱动过程,在高温时则为焓驱动过程。扩张频率越大,体系的扩张模量越高,而相角则随频率的增加不断降低。扩张模量和扩张弹性随浓度升高出现一个最大值,并且最大值出现的位置随频率的降低向低浓度移动,说明低浓度时HPDMA-C₁₂-CD在界面层上累积。温度的变化改变界面浓度和构象,从而改变界面膜的粘弹性。第五章研究了β-CD在水溶液中对碳酸钙在空气—水界面和体相中的结晶和生长的调控,考察了CD浓度、反应时间、CD类型的影响。不加入CD时,观察到碳酸钙在界面上从ACC逐步生长到半球形颗粒的的过程,这个过程包括纳米颗粒的层层自组装过程,半球形颗粒在空气一侧的形貌呈现出“年轮”图样。加入β-CD后,颗粒为圆锥和半球的组合体或七面体、八面体等形貌,由于纳米颗粒的层层自组装,还可以观察到贝壳状的形貌;而增大β-CD的浓度,得到的碳酸钙颗粒的形状与不加β-CD时类似;CD类型对界面上生成碳酸钙形貌的的影响主要与界面上的羟基密度有关,改性CD在界面上的羟基密度较低,对形貌的影响较小。由于采用敞开扩散的方法,ACC向晶体的转变非常快。反应时间越长,碳酸铵的加量越大,颗粒的尺寸越大;CaCl₂浓度增大,颗粒的尺寸降低。XRD和FTIR研究都表明界面上得到的碳酸钙主要是方解石,有少量球霰石。在体相中,加入β-CD后对碳酸钙颗粒的影响不大,仍为纳米颗粒聚集而成的中心突出的圆盘形,但β-CD浓度大于1 mmol·dm^-3后,颗粒的尺寸骤降。方解石与球霰石共存:反应时间较短时,得到的主要是方解石型碳酸钙,随着反应时间的延长,球霰石的比例升高,并最终成为主要组分。在6-HP-β-CD和6-HB-β-CD溶液中形成的碳酸钙颗粒的表面出现类似毛线团的层状堆积结构。更多还原

【Abstract】 Cyclodextrin/surfactants mixtures have not only wide applications in cosmetic, pharmaceutics,and food products,etc.but also have the ability to simulate biological systems, which expedites the penetration of biological technology into chemical industry and medicine field.Therefore,the interest in the interaction between cyclodextrin and surfactant is very high for many years.The interaction between cyclodextrin and surfactant has been widely reported in literature, such as the interaction between CTAB,SDS,TX-100 and cyclodextrin,but less attention has been paid to the effect of additives on the interaction.The property of the surfactant solution, especially ionic surfactant,is affected greatly by the presence of additives,such as electrolyte and polar organic compounds.The addition of electrolyte must have some function on the interaction between alkyltrimethylammonium bromide（CnTAB）,which is a kind of traditional cationic surfactant,and cyclodextrin.The interaction between modified cyclodextrin,which have improvements in the binding and selectivity,and CnTAB would be affected by the chain length of the substituent,the exact positions of the substituent,and the degree of substituent.In this dessertation,the influence of NaBr upon the interaction between TTAB/β-CD and CTAB/β-CD has been studied systematically.The effect of NaCl on the interaction between CTAB andβ-CD was studied as well to show the influence of counterion of the electrolyte.The interaction between modified cyclodextrin（2-HP-β-CD,6-HP-β-CD, 2-HB-β-CD,and 6-HB-β-CD） and CnTAB（TTAB and CTAB） was presented.The interfacial behavior of an amphiphilic cyclodextrin 2-O-（hydroxypropyl-N,N-dimethyl-N-dodecylammonio） -β-cyclodextrin(HPDMA-C₁₂-CD) was investigated using oscillating bubble rheometer and electrical conductivity method at different temperatures.The dispersion effect of naturalβ-CD and modified cyclodextrin to the CNTs was studied.The influence of dispersion effect of CnTAB to the CNTs by the presence ofβ-CD was investigated.This dissertation comprises of five parts.Chapter 1 gives an introduction to the interaction between surfactant and cyclodextrin. Chapter 2 involves three parts.The first part involves an examination of the effect of NaBr and NaCl on the interaction between CTAB andβ-CD.The stoichiometry,R,has been determined by the surface tension method.The ability to form complexes with CTAB:CD ratios of 1:1 and 1:2 are shown to depend on the concentration and counterion of electrolyte. It is found that R first decreases then increases as a function of electrolyte and NaBr increases R more efficiently.The results obtained from the oscillating barrier measurements at low dilational frequencies（0.005-0.1 Hz） reveal that the dilational modulus passes through a maxium value and a minimum value as the concentration ofβ-CD increses at a given concentration of CTAB.The addition of NaBr decreases the dilational modulus of CTAB/β-CD solution at a given concentration of both CTAB andβ-CD.The second part of Chapter 2 deal with the effects on the interaction between CnTAB （n=14 and 16） andβ-CD of NaBr to get an appreciation of the effect of hydrophobic chain length of surfactant.It is concluded from the surface tension data that the adsorption efficiency(pc₂₀) of CTAB are higher than those of TTAB,while the values of cmc^*,cmc/c₂₀ ratio and△G°_mic are somewhat lower.These results demonstrate that the surface activity of CTAB is still higher than TTAB in the presence ofβ-CD.Although the hydrophobic chain of TTAB is shorter than that of CTAB,the TTAB/β-CD complexes can adsorb on the air/water interface as well.The presence of NaBr elongated the effective hydrophobic chain of CnTAB which increases the adsorption of the complexes at the air/water interface,thereforeγ_cmc decreases.As the concentration of NaBr increasing,the effect of the concentration ofβ-CD on theγ_cmc decreases.The adsorption of TTAB/β-CD complexes at the air/water interface decreases the effect of the consumption of TTAB forming complexes to the efficiency of adsorption.The increase in theγ_cmc of CTAB/β-CD in the presence of NaBr could be attributed to the close pack of CTAB at the air/water interface.The third part of Chapter 2 describes the interaction between CnTAB and modified cyclodextrin（6-HP-β-CD,6-HB-β-CD,2-HP-β-CD,and 2-HB-β-CD） using surface tension method.Modified cyclodextrin（MCD） can decrease the surface tension of water itself,and the surface tension of MCD decreases as the concentration of MCD increases.The surface tension isotherm of CnTAB/CD solution has two breaks for a given CD concentration.The surface tension value decreases before the first break,which means that the surface activity of CnTAB/CD complexes is comparable to the one of MCD.The surface activity of MCD varies according to the structure:long substituent,high degree of substituent and substitute on the secondary side of CD result in a high surface activity.The positions of the substituent on MCD affect the interaction between CnTAB and MCD,result in different influences on R, cmc^*,andγ_cmc.When the CnTAB interact withβ-CD and MCD which is modified at the C2-position,R in most complexes is 1:1,result in a higher cmc^*;and for the MCD modified at the C6-position,R in most complexes is 2:1.Theγ_cmc at the CnTAB/C6-position modified MCD and CnTAB/β-CD is lower than that of CnTAB/C2-position modified MCD at lower CD concentration.The interaction between TX-100 and MCD conform that it is the adsorption of complexes,due to the loose pack of CnTAB at the air/water interface,which decrease theγ_cmc of CnTAB/CD solution.The induced circular dichroism spectrum（ICD） shows that it is the interaction between the benzene ring of TX-100 and the hydrogen bond ring in the cavity of CD which produces the induced chirality.A high degree of substituent results in a weak induced chirality in the TX-100/C6-position modified MCD solution.Chapter 3 involves two parts.The first part involves the examination of the dispersion effect of five cyclodextrins,including 2-HP-β-CD,6-HP-β-CD,2-HB-β-CD,6-HB-β-CD, andβ-CD,on carbon nanotubes（CNTs）.2-HB-β-CD is the most efficient dispersing agent.It is found that both the substituted position and the chain length of the substituted group were important for the dispersion of CNTs.The dispersing ability of CDs on the dispersion of CNTs was 2-HB-β-CD＞＞6-HP-β-CD＞β-CD＞6-HB-β-CD＞2-HP-β-CD.The interaction between the CDs and CNTs was studied by Fourier transform infrared spectroscopy（FTIR）, Raman spectrum,and X-ray powder diffraction.The movement in the FTIR spectra of the asymmetric and symmetric stretching vibrations of O-H of the composites means that hydrogen bonding is an important factor on the dispersing ability of CDs.These results indicate that the type of interaction might be the combination of a weak interaction similar to the van der Waals and a hydrogen bonding mechanism.The second part of Chapter 3 deal with the effect of the interaction between CnTAB（n=12, 14,16） andβ-CD on the ability of dispersing CNTs of CnTAB by UV-vis-NIR and Raman spectra observations.Of the three surfactants,the ability of dispersing CNTs of DTAB is the smallest,while it is greatly enhanced in the TTAB and CTAB aqueous solution.The maximum amount of CNTs in TTAB and DTAB solution is similar to each other,but the concentration of CTAB solution to this amount is much lower than that in the TTAB solution. The DTAB solution does not have the ability to disperse CNTs,while the TTAB and CTAB solution could disperse CNTs when the concentration of surfactant is lower than the cmc.The presence ofβ-CD enables the DTAB solution to disperse CNTs even when the concentration is lower than the cmc.The type ofβ-CD self-aggregates affect the ability of dispersing CNTs of CnTAB,and the complexes of the monomer ofβ-CD and CnTAB result in the best dispersing ability before cmc^*.The stability of CnTAB/β-CD/CNTs suspended systems has an improvement probably due to the electrostatic repulsion between the ionic hydrophilic groups of CnTAB and steric hindrance ofβ-CD.Chapter 4 describes the interfacial behavior of HPDMA-C₁₂-CD by oscillating bubble rheometer and electrical conductivity method at different temperatures.The surface tension and interracial dilational viscoelasticiy of HPDMA-C₁₂-CD are provided.The results showed that HPDMA-C₁₂-CD could adsorb on the air/water interface which efficiently decreases the surface tension of water,cmc can be clearly defined from the surface tension isotherm,pc₂₀ andπ_cmc are derived from the surface tension isotherms as well.The thermodynamic parameters（△G°_m,△H°_m,-T△S°_m） derived from electrical conductivity indicate that the micellization of HPDMA-C₁₂-CD varies from entropy driven process to enthalpy driven process.The dilational modulus appeares to have a maximum value while the phase angle have two maximums as a function of the concentration of HPDMA-C₁₂-CD.Chapter 5 involves the effects on the crystallization of calcium carbonate ofβ-CD,which is conducted by an open vapor diffusion method（decomposition of（NH₄）₂CO₃）,including the effect of the concentration ofβ-CD,diffusion time,and the type of CD.Flat concentric circles morphology was observed at the air side of the CaCO₃ particles in the absence ofβ-CD,which gives evidence to the layer-by-layer assembly mechanism.Circular cone morphology was obtained at the air side of the CaCO₃ particles in the presence ofβ-CD, while the morphology is similar to the one withoutβ-CD if the concentration ofβ-CD increases.β-CD accelerats the growth of"circle" particles.Both the prolonged diffusion time and the increasing of the mass of（NH₄）₂CO₃ increase the size of the particles.The time-dependent evolution was studied by SEM.The bulk side of the particles is composed of nanoparticles about 50 nm,and these nanoparticles aggregate to be thin layers which cover the inside particle.FTIR and XRD analysis show that the particles are calcite with only a little vaterite.However,β-CD might just transport Ca²⁺ to the interface rather than form inorganic-organic hybrid with CaCO₃,because the weight loss is not observed in the TG analysis.The particles observed in the bulk are nano-particles assembled center pop out disks. It dramatically decreases the size of the particles when the concentration ofβ-CD increases to 1 mmol·dm^-3.It is a mixture of calcite and vaterite.Calcite is the main component at short diffusion time,while vaterite is the main component at long diffusion time.Layer packed dlipsoid was Observed in the presence of 6-HP-β-CD and 6-HB-β-CD.更多还原