Breaking of the Bancroft rule for multiple emulsions stabilized by a single stimulable polymer

doi:10.1039/c4sm00596a

	Breaking of the Bancroft rule for multiple emulsions stabilized by a single stimulable polymer
	Besnard, L; Protat, M; Malloggi, F; Daillant, J; Cousin, F; Pantoustier, N; Guenoun, P; Perrin, P
刊名	Soft matter
	2014-09-28
卷号	10 期号:36 页码:7073-87
ISSN号	1744-6848
DOI	10.1039/c4sm00596a
文献子类	Article
英文摘要	We investigated emulsions of water and toluene stabilized by (co)polymers consisting of styrene (S) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) monomer units with different compositions and structures such as a PDMAEMA homopolymer, a P(S-co-DMAEMA) random copolymer and various PS-b-PDMAEMA and PS-b-(S-co-DMAEMA) block copolymers. The model system is used to study the fundamental conditions under which the different kinds of polymer-stabilized emulsions (direct oil in water, inverse water in oil and multiple emulsions) are stabilized or destabilized by pH change (at constant temperature). Polymer properties like chain conformation at the toluene-water interface as probed by SANS and neutron reflectivity at the liquid-liquid interface, the oil-water partitioning of the polymer chains (Bancroft's rule of thumb) as determined by UV spectroscopy and interfacial tensions measured by the rising and spinning drop techniques are determined. Overall, results evidence that the curvature sign, as defined by positive and negative values as the chain segments occupy preferentially the water and toluene sides of the interface respectively, reliably predicts the emulsion kind. In contrast, the Bancroft rule failed at foreseeing the emulsion type. In the region of near zero curvature the crossover from direct to inverse emulsions occurs through the formation of either unstable coexisting direct and inverse emulsions (i) or multiple emulsions (ii). The high compact adsorption of the chains at the interface as shown by low interfacial tension values does not allow to discriminate between both cases. However, the toluene-water partitioning of the polymeric emulsifier is still a key factor driving the formation of (i) or (ii) emulsions. Interestingly, the stabilization of the multiple emulsions can be tuned to a large extent as the toluene-water polymer partitioning can be adjusted using quite a large number of physico-chemical parameters linked to polymer architecture like diblock length ratio or polymer total molar mass, for example. Moreover, we show that monitoring the oil-water partitioning aspect of the emulsion system can also be used to lower the interfacial tension at low pH to values slightly higher than 0.01 mN m(-1), irrespective of the curvature sign.
语种	英语
内容类型	期刊论文
源URL	[http://119.78.100.183/handle/2S10ELR8/266692]
专题	中国科学院上海药物研究所
通讯作者	Besnard, L
作者单位	PSL Research University, ESPCI ParisTech, UMR 7615, Laboratoire de Sciences et Ingénierie de la Matière Molle (SIMM), 10 Rue Vauquelin, 75231, Paris, Cedex 05, France. Patrick
推荐引用方式 GB/T 7714	Besnard, L,Protat, M,Malloggi, F,et al. Breaking of the Bancroft rule for multiple emulsions stabilized by a single stimulable polymer[J]. Soft matter,2014,10(36):7073-87.
APA	Besnard, L.,Protat, M.,Malloggi, F.,Daillant, J.,Cousin, F.,...&Perrin, P.(2014).Breaking of the Bancroft rule for multiple emulsions stabilized by a single stimulable polymer.Soft matter,10(36),7073-87.
MLA	Besnard, L,et al."Breaking of the Bancroft rule for multiple emulsions stabilized by a single stimulable polymer".Soft matter 10.36(2014):7073-87.