# Thermoresponsive behavior of poly[trialkyl-(4-vinylbenzyl)ammonium] based polyelectrolytes in aqueous salt solutions

Karjalainen, Erno; Suvarli, Narmin; Tenhu, Heikki

##### Abstract:
This contribution reports 16 new thermoresponsive systems based on poly[trialkyl-(4-vinylbenzyl)ammonium] chlorides. When salts are introduced into solution of the water-soluble polymers, thermoresponsive behavior is observed. The type of transition is dependent on the length of the alkyl chain: the polymer with an ethyl chain has an upper critical solution temperature (UCST) whereas the polymers with butyl or pentyl chains have a lower critical solution temperature (LCST). The magnitude of the effect of a given salt on the solution behavior is dependent on the type of the used electrolyte. With all polymers, the strength of the effect increases in the following order: NaH$_{2}$PO$_{4}$ < Na$_{2}$CO$_{3}$ < Na$_{2}$SO$_{4}$ < NaCl < sodium pentanesulfonate < NaNO$_{3}$ < NaSCN < lithium trifluoromethanesulfonate < lithium bis(trifluoromethane) sulfonimide. For monovalent salts, the order follows a reversed Hofmeister series. The results can be used to design new thermosensitive systems by matching the alkyl content of a polycation with an effect of the small molecular salt. Nearly an unlimited number of thermoresponsive polymers can be designed following the approach introduced in this article.

 Zugehörige Institution(en) am KIT Institut für Bio- und Lebensmitteltechnik (BLT) Publikationstyp Zeitschriftenaufsatz Publikationsjahr 2020 Sprache Englisch Identifikator ISSN: 1759-9954, 1759-9962 KITopen-ID: 1000125580 Erschienen in Polymer chemistry Verlag Royal Society of Chemistry (RSC) Band 11 Heft 36 Seiten 5870–5883 Vorab online veröffentlicht am 19.08.2020 Nachgewiesen in Web of ScienceScopus
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