Generation of Silicone Poly‐HIPEs with Controlled Pore Sizes via Reactive Emulsion Stabilization

Abstract

Macrocellular silicone polymers are obtained after solidification of the continuous phase of a poly(dimethylsiloxane) emulsion, which contains poly(ethylene glycol) drops of sub-millimetric dimensions. Coalescence of the liquid template emulsion is prohibited by a reactive blending approach. The relationship is investigated in detail between the interfacial properties and the emulsion stability, and micro- and millifluidic techniques are used to generate macrocellular polymers with controlled structural properties over a wider range of cell sizes (0.2-2 mm) and volume fractions of the continuous phase (0.1%-40%). This approach could easily be transferred to a wide range of polymeric systems.

Interfacial tension of reactive, liquid interfaces and its consequences

“…Comparing the properties for different pairs of immiscible polymers stabilized by either premade copolymers or in-situ formed copolymers shows that the equilibrium interfacial values are identical with both stabilization routes. For example, Wagner et al [87] measured the interfacial tension between PDMS and PEG with pre-made PDMS-PEG-PDMS and found equilibrium values close to the ones which Giustiniani et al [81] found for PDMS and PEG stabilized by in-situ compatibilization ( Figure 5). As the configuration of the copolymers, in addition to their chemical composition, has an impact on the equilibrium value of interfacial tension γ eq [86,88,89], the comparisons between the reactive and non-reactive cases is not straightforward.…”

“…Experiments show that the relaxation of the interfacial tension of reactive interfaces exhibits a strikingly similar behaviour to that of non-reactive interfaces [81][82][83][84][85][86]. All curves start at a value γ 0 , which is the value of interfacial tension between the two non-reactive phases with no added surfactants.…”

Emulsion and Foam Templating—Promising Routes to Tailor‐Made Porous Polymers

“…Theb iggest disadvantage of this technique is the necessity to remove the dispersed phase, which makes this acost-inefficient procedure for the production of large samples.However,applications are beginning to emerge in which the presence of the dispersed liquid is actually desired. Forexample,the viscosity of the drops allows the adhesive properties of solid silicone emulsions to be tuned, [42] and electrolyte-filled porous polymers can be directly processed into electrode separators in batteries. [43,44]…”

Emulsions‐ und Schaumtemplatierung – vielversprechende Methoden zur Herstellung maßgeschneiderter poröser Polymere

“…B. eine Feineinstellung der adhäsiven Eigenschaften von festen Siliconemulsionen, [42] und Elektrolyt-gefüllte porçse Polymere kçnnen direkt als Elektrodenseparatoren in Batterien verwendet werden. Die Funktion der beiden Flüssigkeiten (interne oder kontinuierliche Phase) kann durch einen entsprechend ausgewählten Emulgator recht einfach umgekehrt werden.…”

“…Die Viskositätd er Tropfen ermçglicht z. B. eine Feineinstellung der adhäsiven Eigenschaften von festen Siliconemulsionen, [42] und Elektrolyt-gefüllte porçse Polymere kçnnen direkt als Elektrodenseparatoren in Batterien verwendet werden. [43,44] Abbildung 4.…”