Lyotropic Lamellar Polysiloxanes with Isomeric Amphiphilic Side Chains

Abstract

Summary: This paper presents the synthesis of two polymeric surfactants, consisting of a polysiloxane backbone with amphiphilic side chains of the nonionic oligo(ethylene oxide) type, and their phase behavior in aqueous solution, investigated by polarizing microscopy and deuterium NMR spectroscopy using D2O as a probe. Two different side chains, which are isomeric glycerol derivatives, were synthesized and attached to poly(methyl hydrogen siloxane) by a hydrosilylation reaction, resulting in a tail‐type and a mid‐type polysurfactant. The side chains of the tail‐type system are fixed at the end of the hydrophobic moiety, whereas the side‐chains of the mid‐type system are tethered to the polymer backbone by a short spacer close to the hydrophilic‐hydrophobic junction of the amphiphile. Both polymers form a lamellar phase in aqueous solution over a wide range of concentrations, whereas the side chain precursors do not form lyomesophases. The cloud curve and the lamellar region are observed at lower temperatures in the mid‐type polysurfactant.Structures of the isomeric polymers forming lamellar phases.magnified imageStructures of the isomeric polymers forming lamellar phases.

Study on Distribution Characteristics and Displacement Mechanism of Microscopic Residual Oil in Heterogeneous Low Permeability Reservoirs

“…Polymeric surfactant (also called active polymer) is a new type of oil displacement agent recently developed and put into field application, which is a group with special functions grafted on the molecular chain of the polymer. Through interactions within and between molecular chains, it realizes the functions of emulsification, viscosity increase, oil washing, and water plugging [20][21][22][23][24]. The main mechanism of enhanced oil recovery by polymeric surfactant flooding is to improve oil displacement efficiency by emulsification while realizing mobility control.…”

Hydrophilized Silicone Matrix for the Preparation of Stable Carbonyl Reductase Immobilizates

“…19 Such silicones are mostly generated by the treatment of “standard” silicone with UV/ozone20 or plasma discharge followed by silanization21 or by incorporation of hydrophilic moieties into the matrix 22. A simple method for the incorporation of hydrophilic compounds involves vinylic groups because these enable direct cross‐linking during hydrosilylation,23 although this requires preliminary modification of the hydrophilic components 24…”

“…The hydrophilization of silicone for the preparation of silCoat biocatalysts was performed with carbonyl reductase from Candida parapsilosis (CPCR2)24 as a model enzyme and poly(ethylene glycol) (PEG) as an environmentally benign and enzyme‐friendly hydrophilizer 23. 25–27 CPCR2 is a synthetically interesting enzyme owing to its broad substrate range and high enantioselectivity26 requiring a distinctly aqueous environment for appropriate activity.…”

Sheetlike Side-Chain Liquid Crystalline Polyacetylenes Forming Monolayer Lamellae in Dilute Solutions

“…At the molecular structure level, side-chain liquid crystalline (LC) polymers always bear chemical heterogeneity. − Therefore, they may adopt “microphase separation” structure in both thermotropoic and lyotropic LC phases. − In smectic or lamellar phases, the backbones incompatible with the side chains form a sublayer squeezed by two adjacent side-chain sublayers. Since mesogenic cores always tend to pack parallel to each other, their separation from spacers/tails on side chains can further develop.…”