Langmuir, Vol.29, No.27, 8452-8458, 2013
Thermoreversible Physical Gels of Poly(dimethylsiloxane) without Cross-Links or Functionalization
The preparation of gels of poly(dimethylsiloxane) (PDMS) reported in the literature so far involves catalysts and chemical cross-links (chemical gels) or functionalization with organogelators. We report that thermoreversible physical gels of PDMS, without cross-links or functionalization, can be made with propylamine or hexylamine as a solvent. The gels consist of spherical domains as small as 20 nm. We show that these spherical domains are part of a network. Differential scanning calorimetry (DSC), optical microscopy, and rheology show that the gel is thermoreversible. With the DSC experiments, we have devised,, a procedure to achieve thermoreversibility with very similar gel-sol transition endotherms in the first and second heating cycles.