Complex new materials from simple chemistry: Combining an amino‐substituted polysiloxane and carboxylic acids

Abstract

Changes in rheological, adhesive, and swelling properties of quaternary salts, made by adding one of eight mono‐ or six α,ω‐alkanedioic acids (the latter with two to six or nine carbon atoms) to 6‐7PSil (a polysiloxane with 6%–7% of the monomer units contain a 3‐aminopropyl group) have been correlated with the salt structures. The simple acid‐base chemistry initiates drastic changes in the bulk properties of the materials that depend on the amount and type of the added acid. Thus, the quaternized forms of the 6‐7PSil have significantly enhanced viscoelastic and adhesive properties compared to those of the initial polysiloxane, and they can swell selectively liquids based on their polarity. Also, interpenetrating networks have been made in situ by photopolymerization of salts with vinylic carboxylic acids. DFT calculations on model systems consisting of dimethylammonium α,ω‐alkanedioate salts with two to six carbon atoms provide insights into the interactions responsible for the unexpected dependence of the properties of the 6‐7PSil salts on the chain lengths of the diacids. The potential for applying the methodologies described here to systems with other amino‐substituted polymers and other acid types is noted. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3851–3861

Neat Linear Polysiloxane-Based Ionic Polymers: Insights into Structure-Based Property Modifications and Applications

“…For example, aminopropyl dimethicone and amodimethicone [21], classes of polysiloxane copolymers with aminopropyl and dimino-containing chains, form emulsions in water. Also, the amino groups can be protonated using mild acids, and even form crosslinks with diacids; in both cases, ion pairs, that alter the local polarity of the polymers, are produced [22]. Although the use of amodimethicone and other polysiloxane-based copolymers in cosmetic [23] and textile products [24] appeared in the 1980s, functionalized ionic polysiloxanes have been introduced more recently.…”

Polydimethylsiloxane as a Matrix for the Stabilization and Immobilization of Zero‑Valent Iron Nanoparticles. Applications to Dehalogenation of Environmentally Deleterious Molecules

“…As reported by He et al, 28 IR spectra showed no evidence for the presence of free -NH 2 (ca. 1570 cm -1 ) in the IR spectra of these samples ( Figure 8); other characteristic signals at ca.…”

“…Amino-substitution on side chain groups in NH 2 PDMS allows the polymer chains to interact specifically with a variety of functional groups which, in turn, produce materials whose microscopic and bulk properties can be very different from those of the parent PDMS. In that regard, it has been shown that the NH 2 PDMS are able to create ion pairs with the triatomic molecules, CO 2 and CS 2 , 27 and with mono-and di-carboxylic acids 28 to produce crosslinks in which the resulting materials have a variety of attractive swelling, rheological, and adhesive properties. A generic NH 2 PDMS containing monomers with 3-aminopropyl side chains and an alkanedioic acid (mDCA, where m is the number of carbon atoms in the chain) react to form ionic crosslink through formation of carboxylate anions and ammonium cations.…”

Uncharged Lewis bases yield polydimethylsiloxane ionomers with amidinium alkyldithiocarbamate side chains

“…In general, when a pendant group like the alkyldithiocarbamates employed here or others are >12 carbon atoms in length or are substituted with an aromatic ring, the PDMS polymers can solidify at room temperature 12,13 . Last, hydrophobic ionomers based on PDMS copolymers have found realized and potential applications in fields such as battery technology, 14,15 adhesives, 5,16 anti‐microbials, 16,17 and stimulus‐responsive materials 5 …”