Hydrophilic chain length

This paper is largely confined to the alkyl and aryl polyoxyethylene ethers, as these form series variable in both hydrophobic and hydrophilic chain length, and hence HLB, with minimal structural variation. 

The influence of hydrophilic chain length and alkyl chain length of a series of alkyl ethers respectively) on the percentage change in blood glucose on administration rectally of insulin with the surfactants. The upper plot shows the results 30 minutes after administration and the lower plot results after 60 minutes. (Redrawn from data in Touitou et al, 1978). 

H. Saito and K. Shinoda The Stability of W/O Type Emulsions as a Eunction of Temperature and of the Hydrophilic Chain Length of the Emulsifier. J. Colloid Interface Sci. 32, 647 (1970). 

Figure 1 summarizes the significant structural features of four classes of nonionic surfactants discussed in this paper. These are simplified representations of commercial surfactants which contain varying hydrophobe and hydrophile chain lengths. The hydrophiles are represented as polyoxyethylene chains, although such hydrophiles as polyglucosides and polyoxypropylene/polyoxyethylene chains are used to a lesser extent. 

It has been demonstrated for several copolymers that the onset of micellization is mainly dependent upon the length of the hydrophobic polymer chains, while the effect of the hydrophilic chain length on the CMC is less pronounced (AstaLeva et al., 1993 Gao and Eisenberg, 1993 Kataoka et al., 1993). AstaLeva et al. (1993) measured the CMC of a range of block copolyelectrolytes based on styrene (the insoluble block) and sodium acrylate. The lengths of the styrene blocks ranged from... 

ACN is the carbon number (or equivalent) of the alkane used, f(C/1) is a function of the alcohol concentration used as a cosurfactant, ct is a parameter characteristic of the chemical structure of the surfactant used (which increases linearly with the hydrophilic chain length),... 

Saito, H. and Shinoda, K. (1970) Stability ofW/O type emulsions as a function of temperature and of hydrophilic chain length of emulsifier. /. Colloid Interface Sci., 32, 647. 

H Saito, K Shinoda. The stability of W/O type emrUsionsas a function of temperature and of the hydrophilic chain length of the emulsifier. J Colloid Interface Sci 32 617, 1970. 

HAM Hamada, N. and Einaga, Y., Effects of hydrophilic chain length on the characteristics of the micelles of octaoxyethylene tetradecyl C Eg, hexadecyl QsEg, and octadecyl CigEg ethers, J. Phys. Chem. B, 109,6990, 2005. 

IMA Imanishi, K. and Einaga, Y., Effects of hydrophilic chain length on the... 

With increased temperature or shortened hydrophilic chain length the cloud-point will be exceeded, the surfactant will become oil soluble and inverse micelles form consecutively when the water concentration is increased. 

H., Effect of Hydrophilic Chain Length of Amphiphdic Sdicone Od (Copolymer) on the Nonionic Surfactant-Layer Curvature. J. Phys. Chem. B 2004,108, 12736-12743. 

The PEO-lipid (12,13) represents another type of amphiphiles. Spread molecules of PEO-lipid (12,13) form stable monolayers with hydrophobic C12 chains protruding into the air phase and the hydrophilic poly(ethylene oxide) chain immersed in the aqueous subphase. The com-pressional behavior of such a molecule strongly depends upon the hydrophilic chain length [10]. While an amphiphile with a short PEO chain (5 ethylene oxide monomers) was shown to form condensed-type monolayers characteristically displaying a steep increase in surface pressure, a moderate slope, characteristic of an expanded film behavior was observed for longer PEO chain Hpid... 

Recently, polyoxyethylene oleyl ethers were made of high-purity oleyl alcohol (99.7%) synthesized from high-purity oleic acid [3]. In this paper, the effect of hydrophilic chain length on the phase behavior and the structures of liquid crystals in polyoxyethylene oleyl ether/water system were investigated by means of phase study and small-angle X-ray scattering (SAXS). 

The high consumption figure of ethylene oxide-derived surfactants is due to several factors the surfactants are relatively easy to manufacture, they are relatively inexpensive, and they can be derived from a variety of hydrophobic feedstocks, including oleochemical- and petrochemical-based alcohols, and petrochemical-based alkylphenols and alkylamines. Because their hydrophobe and hydrophile chain lengths can be varied significantly, they fit a wide range of applications. 

Until more is known of the molecular interactions of surfactants with membrane components and the factors controlling such interactions it will remain virtually impossible to predict which surfactants will be capable of enhancing permeability of membranes without causing damage. Careful choice of solubilizer both of appropriate structure and optimum concentration is obviously paramount. In experiments on goldfish the effects of polyoxyethylene non-ionic surfactants on the absorption of various barbiturates is dependent on the surfactant hydro-phobic and hydrophilic chain lengths and possibly also on the size of the... 

Figure 8.20 The effect of hydrophilic chain length of emulsifiers on the types and stability of cyclohexane-water emulsions stabilized with 3 % w/w system of CgHi C H 0(CH2CH20) H at 25° C. (O, ) drained phase-cream boundary ( ) coalesced phase-cream boundary. From Shinoda and Sagitani [114] with permission.

Nonionic surfactant molecules contain a polar hydrophilic group (often a polyoxyethylene chain) and a non-polar (lipophilic) chain this character is called amphipathy or amphilicity and results in a double affinity which can only be satisfied at a polar-non-polar interface. Commercial nonionic surfactants are polydisperse, having a distribution of hydrophilic chain lengths they are sold as having an average chain length. Nonionic-oil-water systems are usually pseudo ternary , i.e. the surfactant may be a mixture of surfactants, the aqueous phase may... 

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