Monitoring mesoglobules formation in PNIPAm solutions using Nile Red solvatochromism

作者：Locatelli Champagne Clementine; Cloitre Michel^*

来源：Colloid and Polymer Science, 2013, 291(12): 2911-2916.

DOI：10.1007/s00396-013-3035-5

• Solvatochromism
• Nile Red
• PNIPAm
• Thermosensitive polymer
• Lower critical solubility temperature
• Mesoglobule

Nile Red solvatochromism is used to monitor phase separation in concentrated poly(N-isopropyl acrylamide) (PNIPAm) aqueous solutions. Below the lower critical solution temperature (LCST), Nile Red molecules are in a polar environment and thus exhibit negligible fluorescence. Above the LCST, the aggregation of the PNIPAm chains into hydrophobic mesoglobules provides a nonpolar environment, causing a strong increase of fluorescence. The spectra show two emission bands, which can be related to the partitioning of Nile Red molecules between the core and the surface of the mesoglobules. More generally, the technique appears as a new and promising tool to probe microheterogeneities in polymer solutions or mixtures.

• 出版日期2013-12