Tailoring of the porous structure of soft emulsion-templated polymer materials

Abstract

This paper discusses the formation of soft porous materials obtained by the polymerization of inverse water-in-silicone (polydimethylsiloxane, PDMS) emulsions. We show that the initial state of the emulsion has a strong impact on the porous structure and properties of the final material. We show that using a surfactant with different solubilities in the emulsion continuous phase (PDMS), it is possible to tune the interaction between emulsion droplets, which leads to materials with either interconnected or isolated pores. These two systems present completely different behavior upon drying, which results in macroporous air-filled materials in the interconnected case and in a collapsed material with low porosity in the second case. Finally, we compare the mechanical and acoustical properties of these two types of bulk polymer monoliths. We also describe the formation of micrometric polymer particles (beads) in these two cases. We show that materials with an interconnected macroporous structure have low mechanical moduli and low sound speed, and are suitable for acoustic applications. The mechanical and acoustical properties of the materials with a collapsed porous structure are similar to those of non-porous silicone, which makes them acoustically inactive.

Soft porous silicone rubbers with ultra-low sound speeds in acoustic metamaterials

“…The soft porous silicone rubbers used in this work were synthesized via an emulsion-templated procedure1824. The silicone network was formed by a polyaddition reaction of SiH and SiVi in a mixture with a platinum-based catalyst.…”

Coumarin‐4‐ylmethyl‐ and p‐Hydroxyphenacyl‐Based Photoacid Generators with High Solubility in Aqueous Media: Synthesis, Stability and Photolysis

“…Kovalenko et al . for instance applied commercially available diaryliodonium tetrakis (pentafluorophenyl) borate (Silcolease UV Cata211) with low toxicity, but needed 2‐isopropylthioxanthone as photosensitizer to tailor the porous structure of polydimethylsiloxane foams . A further example where strong electrolyte PAGs were favoured was published by Schlögl et al .…”

A Porous POSiSil Suited for Pressure‐Driven Reversible Confinement of Solutions: PSS‐2

“…in chemical applications, these materials should be made porous, either randomly, or preferably in an ordered fashion. Porous polysiloxanes have been generated by addition of sacrificial templates or by foaming techniques applied during crosslinking . For branched polysiloxanes built up from cross linked D4R units however, the introduction of porosity has hardly ever been achieved …”

“…Porous polysiloxanes have been generated by addition of sacrificial templates or by foaming techniques applied during crosslinking. [25][26][27][28] For branched polysiloxanes built up from cross linked D4R units however,t he introduction of porosityh as hardly ever been achieved. [19,29] Up to now,m ost D4R-polysiloxane copolymers have been obtained by reactions of dimethyldichlorosilane with D4R cyclosilicate molecules dissolved in water.…”