| Ionic liquid Gemini imidazolium surfactant is a new class of amphiphilic molecules with ionic liquid properties,which have better surface activity and aggregation behavior.Gemini imidazolium surfactants contain imidazolium moieties as hydrophilic head groups and they could display stronger tendency to self-aggregation to different aggregates in aqueous solutions,which is owing to the distinct interaction between imidazolium head groups.When ionic liquid Gemini surfactant forms reverse micelles with hydrophobic group outside and hydrophilic group inside,they could display better solubilization.Ionic liquid Gemini surfactants have wide applications in nanomaterial template,biological membrane simulation,the synthesis and release of drugs and oilfield development for their unique nature and rich aggregation structures.The thesis studied the synthesis method of ionic liquid Gemini surfactants with different alkyl chain length and characterized the chemical structure and purity of objective products.Their surface activity and aggregation behavior were studied.The thermodynamic parameters of micellization,micelle polarity and aggregation number of micelles were calculated.The aggregation behavior and the structure of aggregates for [C12-3-C12im]Br2/D2 O system was studied by 1H-NMR and 2D NOESY methods.The formation of IL/O and W/O microemulsion phase region which was involved [C12-3-C12im]Br2 surfactant was drawn by dilution method.The microemulsion droplet interface parameters and the thermodynamic parameters of microemulsion formation process were calculated.This thesis contains four parts:(1)Synthesis of IL Gemini imidazolium surfactants [Cn-3-Cnim]Br2(n=8,10,12)Imidazole,sodium hydroxide,alkyl bromide as raw material and the surfactant mononer moiety N-alkyl imidazolium was firstly synthesized.Then add 1,3-dibromopropane as spacer to synthesize IL Gemini surfactants [Cn-3-Cnim]Br2(n=8,10,12)with three different alkyl chain length.The structure of object products was characterized by FT-IR,1H-NMR and elemental analysis,and the purity of object products was characterized by HPLC.The analysis results showed that this method successfully synthesized the object products and gained a high purity(>99%).(2)Surface properties and micellization behavior of [Cn-3-Cnim]Br2(n=8,10,12)The cmc and surface properties of IL Gemini surfactants [Cn-3-Cnim]Br2(n=8,10,12)was studied by surface tension method and compared with [Cnmim]Br and [Cn-4-Cnim]Br2(n=10,12).The results indicated that the surface activity of Gemini imidazolium surfactants was much better than monomer imidazolium surfactants and the cmc value decreased with the increase of alkyl chain length.?max increased with alkyl chain length increasing.The cmc and counterion binding ? of [Cn-3-Cnim]Br2(n=8,10,12)aqueous solution at different temperatures could be obtained by conductivity method and the thermodynamic parameters can be calculated from cmc and ?.?Gm? of all system were negative which were indicated that the formation of micelles is a spontaneous process.From the contribution analysis of ?Hm? and T?Sm? to ?Gm? can indicate that [C10-3-C10im]Br2 and [C12-3-C12im]Br2 micelle formation are entropy process and [C8-3-C8im]Br2 micelle formation is enthalpy-driven process.The results of Fluorescence spectrum and DLS showed that the micropolarity and mean aggregation number of micelles decreased with the increase of alkyl chain length.Meanwhile,[C12-3-C12im]Br2 micelles appeared more distributions state but mainly existed in small micellce size in aqueous solutions and formed a little rod-shaped and wormlike micelles.(3)cmc and micelle structure of [C12-3-C12im]Br2/D2 O system studied by NMRBy measuring 1H-NMR of [C12-3-C12im]Br2/D2 O system at different concentration and analyzing the chemical shift variation can obtained the cmc which was in accord with the cmc from surface tension,conductivity and fluorescence methods.When the concentration is much larger than cmc,it can see the intensity and scope of intermolecular cross-peak become larger and greater from 2D NOESY spectrum,which was meant that the molecules packed more closely in aggregates.Cryo-TEM images proved that it formed the rod-shaped and wormlike micellar aggregates when the concentration is much larger than cmc.(4)The formation of IL/O and W/O microemulsion involved in [C12-3-C12im]Br2Two single-phase region miceoemulsion diagrams which [C12-3-C12im]Br2 surfactant was involved in the formation of IL/O and W/O microemusions showed that IL/O microemusion single-phase region is much larger than W/O.IL/O microemusion single-phase region increase but W/O microemusion single-phase region decrease with temperature increasing.Interface parameters of microemulsion droplets variation with different mole ratio R and different temperatures.The thermodynamic process of two microemulsions system were spontaneous... |
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