Non-ionic polymeric surfactants

Figure 2 Schematic representation of the linear and semi-branched architectures of two non-ionic polymeric surfactants...

Here we review the results obtained [4—10] with two types of non-ionic polymeric surfactants (i) A-B-A triblock copolymers and (ii) novel graft polymeric surfactants based on inulin. 

The formation of such Newton black films, that is, bilayer films stabilized by polymeric surfactants deserves special attention. NBF formation in emulsion films from non-ionic polymeric surfactants was first established in Ref [8]. For the case of... 

The aim of the present work was optimization of synthesis of SG -polymeric cation exchanger composite films by sol-gel technology in the presence of non-ionic surfactants and their application for detenuination of Zn (II) as phenanthrolinate (Phen) complex. 

Exploiting ATRP as an enabling technology, we have recently synthesised a wide range of new, controlled-structure copolymers. These include (1) branched analogues of Pluronic non-ionic surfactants (2) schizophrenic polymeric surfactants which can form two types of micelles in aqueous solution (3) novel sulfate-based copolymers for use as crystal habit modifiers (4) zwitterionic diblock copolymers, which may prove to be interesting pigment dispersants. Each of these systems is discussed in turn below. 

Poly(alkylene oxide)-based (PEO-PPO-PEO) triblock and diblock copolymers are commercially successful, linear non-ionic surfactants which are manufactured by BASF and ICI. Over the last four decades, these block copolymers have been used as stabilisers, emulsifiers and dispersants in a wide range of applications. With the development of ATRP, it is now possible to synthesise semi-branched analogues of these polymeric surfactants. In this approach, the hydro-phobic PPO block remains linear and the terminal hydroxyl group(s) are esteri-fied using an excess of 2-bromoisobutyryl bromide to produce either a monofunctional or a bifunctional macro-initiator. These macro-initiators are then used to polymerise OEGMA, which acts as the branched analogue of the PEO block (see Figures 2 and 3). 

Coatings emulsions are generally formed by addition polymerization of common, highly available monomers, using free radical initiators to create polymers having molecular weights from a few thousand up to millions. The polymerization is most often stabilized by non-ionic and/or anionic surfactants, which emulsify the insoluble monomer droplets, and then stabilize the resulting particles, usually in the shape of a sphere. In addition to surfactants, emulsions are sometimes stabilized with water-soluble poly-... 

Derivatives of acyclic olefins can be used as chain transfer agents in these polymerizations. The most effective are those with a terminal double bond. For example, in the ROMP of 248 catalysed by [Ru(H20)6](0Ts)2 the transfer constant (klr/kp) for CH2=CHCH2CH20H is 0.21. The size of the polymer particles produced by emulsion polymerization of 248, using RUCI3 with a non-ionic surfactant, is of the order of 0.03 /zm577. 

The polymerization of styrene in Winsor I-like systems by semi-continuous feeding of monomer stabilized by either DTAB, TTAB or CTAB has been systematically investigated by Gan and coworkers [69a]. Rather monodisperse polystyrene microlatexes of less than 50 nm with molecular weights of over one million were obtained at a polymer/surfactant weight ratio of 14 1. The Winsor I-like (micro)emulsion polymerization of styrene stabilized by non-ionic surfactant and initiated by oil-soluble initiators has also been reported very recently [69b]. The sizes of the large monomer-swollen particles decreased with conversion and they merged with growing particles at about 40-50% conversion. 

The development of transparent polymer electrolyte membrane from the bi-continuous-microemulsion polymerization of 4-vinylbenzene sulfonic acid Hthium salt (VBSIi), acrylonitrile and a polymerizable non-ionic surfactant, co-methoxypoly(ethylene oxide)4o-undecyl-a-methacrylate (Ci-PEO-Cn-MA-40) was reported in 1999 [94,95]. The ionic conductivities of the polymer electro-... 

Fig. 8 SEM micrograph of the polymerized microemulsion solid, that contains the polymerizable non-ionic surfactant Ci-PEO-C,-MA-40 [96], after ethanol extraction...

Most non-polymeric antistatic finishes are also surfactants that can orient themselves in specific ways at fibre surfaces. The hydrophobic structure parts of the molecule act as lubricants to reduce charge buildup. This is particularly true with cationic antistatic surfactants that align with the hydrophobic group away from the fibre surface, similar to cationic softeners (see Chapter 3, Fig. 3.1). The main antistatic effect from anionic and non-ionic surfactants is increased conductivity from mobile ions and the hydration layer that surrounds the hydrophilic portion of the molecule since the surface orientation for these materials places the hydrated layer at the air interface. 

Vineland, NJ) or over-the-counter cosmetic creams promoted for improved hydration (L Oreal, Paris and Dior, Paris). More recently, parenteral liposome formulations of amphotericin B, doxorubicin, and dau-norubicin have been approved and marketed (ABELCET, Elan, the Liposome Co., Inc, Princeton, NJ AmBisome and DaunoXome, Nexstar/Fujisawa, Deerfield Park, IL Amphotec and Doxil, Sequus/ Alza, Menlo Park, CA), with others on the horizon for applications in photodynamic therapy. Although the vast majority of liposome preparations are constructed from phospholipids, other nonphospholipid materials can be used either alone or in mixtures to form bilayer arrays. One such example is Amphotec, which utilizes sodium cholesteryl sulfate as the primary lipid. Other liposome forming materials may include but are not limited to fatty-acid compositions, ionized fatty acids, or fatty acyl amino acids, longchain fatty alcohols plus surfactants, ionized lysophospholipids or combinations, non-ionic or ionic surfactants and amphiphiles, alkyl maltosides, a-tocopherol esters, cholesterol esters, polyoxyethylene alkyl ethers, sorbitan alkyl esters, and polymerized phospholipid compositions. ° ... 

Classical theories of emulsion stability focus on the manner in which the adsorbed emulsifier film influences the processes of flocculation and coalescence by modifying the forces between dispersed emulsion droplets. They do not consider the possibility of Ostwald ripening or creaming nor the influence that the emulsifier may have on continuous phase rheology. As two droplets approach one another, they experience strong van der Waals forces of attraction, which tend to pull them even closer together. The adsorbed emulsifier stabilizes the system by the introduction of additional repulsive forces (e.g., electrostatic or steric) that counteract the attractive van der Waals forces and prevent the close approach of droplets. Electrostatic effects are particularly important with ionic emulsifiers whereas steric effects dominate with non-ionic polymers and surfactants, and in w/o emulsions. The applications of colloid theory to emulsions stabilized by ionic and non-ionic surfactants have been reviewed as have more general aspects of the polymeric stabilization of dispersions. ... 

Fig. 7.9. Schematic representation of the influence of added non-ionic surfactants on cluster growth in a TEOS derived polymeric sol. (a) TEOS alcoholic solution (b) TEOS standard sol (c) aged sol in the presence of surfactant (d) aged sol without surfactant [65].

In dispersion polymerization, by contrast to emulsion or suspension polymerization, a monomer which is soluble in the reaction medium is polymerized. In analogy to fhe aforementioned types of polymerization, an insoluble polymer is obtained. The reaction is carried out in the presence of non-ionic surfactants or soluble polymers, which can stabilize the polymer particles generated to form a stable latex. Wifh particle sizes of ca. 1 to 15 pm, dispersion polymerization can cover the particle size range between emulsion and suspension polymerization. 

In addition to a proper choice of ligand hydrophobicity, the surfactant used is also critical. In general, non-ionic surfactants were found to be efficient for colloidal stabilization of the polymer particles [221]. This is to be expected, as, owing to the ionic nature of the catalyst, and the corresponding ionic strength, electrostatic stabilization is likely to be poor. Adequate hydrophilic/lipophilic balance (HLB) [222] is also a necessary criterion to ensure latex stability in ATR emulsion polymerization [223]. 

Petrochemical surfactants are mainly derived from ethylene, propylene, butylenes, benzene, and also naphthalene as building blocks [46]. The most important emulsifiers for emulsion polymerization are anionic and non-ionic surfactants. Cationic and amphoteric surfactants are only used in special cases and are of minor importance as emulsifiers for polymerization. 

These esters were prepared from aqueous solutions of tri-ethanolamine and PE-61.PE-62 and PE-64 block copolymers. When higher monoesters of the surface active agents were utilized, excellent antiwear properties were observed. Again, the configuration of the ether linkage in relationship to the rest of the molecule plays a role in this compound s effectiveness. Table 2.4 shows properties of cutting fluids from ricinoleic acid oligomer esters with triethanolamine. The same values from fluids made from polymeric non-ionic surfactants are shown in Table 2.5. 

Figure 14.13 Oil-in-water emulsions may be stabilized by (A) non-ionic surfactants, [B) poloxamer block copolymers or [C) polymeric materials. The hydrophilic chains produce repulsion by mixing interaction [osmotic) or volume restriction [entropic).

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