Molecular design of amphotropic materials: double-headed diol-based mesogens incorporating rigid structural units

Hentrich, Frank; Tschierske, Carsten; Diele, Siegmar; Sauer, Christiane

doi:10.1039/jm9940401547

Cited by 31 publications

(17 citation statements)

References 10 publications

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“…In regard to the newly synthesized surfactants with expectation of further development of surfactant performance, some new types of surfactants, e.g., Gemini (9) and Bola (10) have been prepared. In 1971, Bunton first synthesized a type of cationic Gemini surfactant (11), and since then different kinds of Gemini surfactants with cationic (12), anionic (13) and neutral (14) head groups have been synthesized.…”

Section: Introductionmentioning

confidence: 99%

Adsorption and Micelle Formation of Mixed Surfactant Systems in Water II: A Combination of Cationic Gemini-type Surfactant with MEGA-10

et al. 2003

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Mixed micellization and mixed adsorbed film formation were investigated for the combination of a Gemini type cationic and a nonionic surfactants mixture: Bis-trimethyl ammonium Gemini derived from tartaric acid bromide (BAGTB) and n-Decanoyl-Nmethylglucamide (MEGA-10). The surface tension of the aqueous mixed surfactant solution was measured at every 0.1 mole fraction of MEGA10 in the surfactant mixture applying a drop volume method at 30. From the curves of surface tension (g) vs logarithmic concentration in molality (ln m), critical micellization concentration (CMC), minimum surface tension at CMC (g CMC), surface excess (G), mean surface area occupied by a molecule (A m) and parameters related to synergism in surface activity such as pC 20 and CMC / C 20 were determined. Based on the regular solution theory, the relation of compositions of the singly dispersed phase (X MEGA10) and the micellar phase (Y MEGA10), and the relation of X MEGA10 with the composition in adsorbed film phase (Z 2) were estimated, and along with these, the interaction parameters in micelles (w R) and in adsorbed film (w A) were calculated. Both the CMC-X MEGA-10 and CMC-Y MEGA-10 curves showed a negative deviation from ideal mixing and even the curve of Z MEGA10-m t (bulk phase concentration) produced a slightly negative w A. However, the synergism in surface tension reduction was found to be rather weak from examination of partial molecular area (PMA) and the minimum free energy at surface G min (S) = (g CMC A m L). As for the adsorbed film, the interaction mode between molecules, as well as two dimensional molecular packing, was observed to be separated into three regions; i. e. at X STDS = 0.45 and at X STDS = 0.75 different properties changed discontinuously.

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Section: Introductionmentioning

confidence: 99%

Adsorption and Micelle Formation of Mixed Surfactant Systems in Water II: A Combination of Cationic Gemini-type Surfactant with MEGA-10

et al. 2003

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“…The syntheses were performed by phase transfer-catalyzed etherification of 2'-bromomethyl-4,4'-didecyloxyterphenyl [ 111 with appropriate isopropylidene-protected triols followed by acidolytic deprotection according to reference [12].…”

Section: Methodsmentioning

confidence: 99%

Formation of columnar mesophases by rod‐like molecules: Facial amphiphilic p‐Terphenyl derivatives

et al. 1997

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The liquid‐crystalline behavior of rod‐like mesogens is normally associated with the formation of smectic layer structures. However, it is shown that the introduction of large hydrophilic groups in a lateral position, such as in the Figure, can lead to columnar mesophases. The formation of columnar mesophases by rod‐like molecules is suggested to be a more general phenomenon than currently thought. magnified image

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“…On continued cooling of the sample, at 115.3 1C, the homeotropic region shows dendritic growth and transforms into platelet texture typical of crystal E phase. 42 The crystallization of the sample is noticed on cooling the crystal E phase at 78 1C. The T4 mesogen (Fig.…”

Section: Mesophase Assignment By Hopm and Dscmentioning

confidence: 99%

“…On continued the sample, at 115.3 °C, the homeotropic region shows dendritic growth and transforms into platelet texture typical of crystal E phase 42. 4A-C, ESI) reveals the presence of nematic, smectic A (SmA) and crystal E phases.…”

mentioning

confidence: 99%

2-Octyl thiophene based three ring mesogens: solid state ¹³C NMR and XRD investigations

Veeraprakash

Lobo

Narasimhaswamy

et al. 2015

Phys. Chem. Chem. Phys.

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2-Octyl thiophene based three-ring mesogens namely 4-n-alkoxyphenyl 4-(5-n-octyl-2-thienyl)benzoates are synthesized by employing palladium acetate based direct arylation. The alkoxy terminal is varied with even carbons from C2 to C14 and enantiotropic polymesomorphism is noticed for all the homologs. Accordingly, phase sequence consisting of nematic, smectic A, smectic C and smectic B is seen for mesogens with terminal chains C6, C8, C10 and C12 on cooling the isotropic phase. For mesogens with C2, C4, C8 and C10 terminal alkoxy chains, the mesophase assignment from hot-stage optical microscopy and differential scanning calorimetry is further confirmed by variable temperature powder X-ray diffraction measurements. The appearance of smectic B phase is established by noticing sharp and intense peaks in both small-angle and wide-angle regions. For a representative mesogen, i.e. T10, high-resolution solid-state (13)C NMR investigations are carried out in all the phases, viz. nematic, smectic A, smectic C and smectic B phases. The orientational order parameters calculated from (13)C-(1)H dipolar couplings from 2D SAMPI-4 experiments are found to be 0.44, 0.67, 0.73 and 0.79 in nematic, smectic A, smectic C and smectic B mesophases for the center phenyl ring respectively. Remarkably, the thiophene order parameter in all mesophases is found to be higher than that of phenyl rings and is explained by considering the molecular shape, which has a terminal bend. Further, the mesogens are found to be photoemissive in chloroform solution with an emission band at ∼410 nm.

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Molecular design of amphotropic materials: double-headed diol-based mesogens incorporating rigid structural units

Cited by 31 publications

References 10 publications

Adsorption and Micelle Formation of Mixed Surfactant Systems in Water II: A Combination of Cationic Gemini-type Surfactant with MEGA-10

Adsorption and Micelle Formation of Mixed Surfactant Systems in Water II: A Combination of Cationic Gemini-type Surfactant with MEGA-10

Formation of columnar mesophases by rod‐like molecules: Facial amphiphilic p‐Terphenyl derivatives

2-Octyl thiophene based three ring mesogens: solid state ¹³C NMR and XRD investigations

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Molecular design of amphotropic materials: double-headed diol-based mesogens incorporating rigid structural units

Cited by 31 publications

References 10 publications

Adsorption and Micelle Formation of Mixed Surfactant Systems in Water II: A Combination of Cationic Gemini-type Surfactant with MEGA-10

Adsorption and Micelle Formation of Mixed Surfactant Systems in Water II: A Combination of Cationic Gemini-type Surfactant with MEGA-10

Formation of columnar mesophases by rod‐like molecules: Facial amphiphilic p‐Terphenyl derivatives

2-Octyl thiophene based three ring mesogens: solid state 13C NMR and XRD investigations

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2-Octyl thiophene based three ring mesogens: solid state ¹³C NMR and XRD investigations