Zwitterionic Silicone Materials Derived from Aza‐Michael Reaction of Amino‐Functional PDMS with Acrylic Acid

Abstract

Supramolecular zwitterionic silicones are synthesized by aza‐Michael reaction between acrylic acid and amine‐functional polydimethylsiloxanes. The in‐depth characterization of this chemistry, applied for the first time to silicones, is investigated first with model alkylamines (hexylamine, 2‐ethylhexylamine and N‐propylethylenediamine), a model oligosiloxane (3‐aminopropylmethyl bis(trimethylsiloxy)silane), and finally various amino‐polysiloxanes. It is shown that after a first acid–base reaction resulting in ionic pairing, aza‐Michael addition proceeds smoothly in mild conditions (50 °C, 1‐week reaction). Both monoadducts and di‐adducts, together with residual amine, are observed by NMR. The supramolecular assembly of the thus‐created zwitterionic moieties is highlighted by a concomitant increase in viscosity and phase separation, as observed by transmission electron microscopy, bringing an additional glass transition at –40 °C assigned to highly polar ionic clusters. Below the stoichiometry in acrylic acid, all zwitterionic silicones follow the same classical behavior of nonentangled polymers according to the Rouse model, whereas upon introducing an excess of acrylic acid to amino groups, an enhancement of the elasticity is observed. Finally, silicone elastomers with solid‐like behavior and elastomeric mechanical properties are obtained using a high molar mass polymer bearing bifunctional N‐(2‐aminoethyl)‐3‐aminopropyl units that favor a high degree of physical crosslinking.

Hemin‐Doped, Ionically Crosslinked Silicone Elastomers with Peroxidase‐Like Reactivity

“…[29,30] That methodology requires aromatic alcohols or ethers on the porphyrin that, unfortunately, hemin does not possess. [31,32] Thermoplastic silicone networks that are ionically crosslinked through the interactions between aminosilicones and carboxylic acids have been reported; [33][34][35] the use of ethylenediamino-modified silicones leads to particularly robust elastomers through "gemini" interactions. [32] Based on the reports of ionically crosslinked hemins noted above, [21] we reasoned this strategy could also be adopted for silicone/ hemin elastomers.…”

Polymer Ligand Design and Surface Modification of Ag Nanowires toward Color-Tone-Tunable Transparent Conductive Films

“…Furthermore, a new signal corresponding to the new proton site (2 h') generated by the Michael addition appeared at 2.85 ppm. 36 Additional new signals corresponding to 2 h and 2i sites are also expected to appear at ∼3.76 and 2.50 ppm 34 after the reaction; however, these signals overlapped with those from PEG or PEI. These results suggest that all the acryloyl groups of mPEGA were successfully consumed by the Michael addition reaction with the amine groups of PEI.…”

Chelating Silicone Dendrons: Trying to Impact Organisms by Disrupting Ions at Interfaces

“…The self-association of carboxylic acid groups in a silicone environment through hydrogen bonding dramatically increases viscosity and makes the polymers more difficult to process. However, the tunable acidity allows carboxy-modified silicones to be used as constituents of ionic liquids [ 23 ], or ionically crosslinked elastomers ( Figure 1 b) [ 24 , 25 , 26 ].…”

“… ( a ) Traditional chelating multidentate ligands. ( b ) Silicone elastomers crosslinked through ionic interactions [ 24 , 25 ]. ( c ) Example of a dendrimer prepared using the PR reaction [ 30 , 31 ].…”