Molecular modeling of thermo-responsive hydrogels: observation of lower critical solution temperature

A new class of nanoengines based on thermoresponsive polymers: Conceptual design and behavior study

“…In other words, above the LCST, the PNIPAM molecules have smaller average extent [19]. For the endgrafted chains in our system, we observe the LCST around or slightly below 305 K; a value which coincides reasonably well with available experimental data [18,[31][32][33][34][35] and other simulation results of free PNIPAM chains [19,24,[36][37][38][39].…”

“…Here, we employ an intermolecular hydrogen bond definition which is similar to the one used in Ref. [38]; a pair is termed hydrogen bonded if the donor-acceptor distance is less than 3.6 Å, the hydrogen-acceptor distance is less than 2.45 Å, and the donor-hydrogen acceptor angle is less than 30 . Water-PNIPAM hydrogen bonds exist in two types; (i) PNIPAM is donor and water is acceptor, and (ii) PNIPAM is acceptor and water is donor.…”

Thermo‐Switchable Antibacterial Activity

“…Thereby the increased maximum reduction in the copolymer 5/PEGDE 2:1 coating compared to 1:1 and 1:1.5, respectively, can be attributed to a slightly higher content of copolymer 5 on the fabric surface, according to the results from EDX analysis, and the larger gap between killed bacteria below or above the phase transition point however must be due to a hindered mobility of poly(AEMA‐ co ‐NIPAAm) chains in the crosslinked structure. MacElroy and coworkers contributed to this topic by means of molecular simulation techniques; they showed a hindrance of self‐association at the LCST with increasing crosslinking density for a PNIPAAm hydrogel 36. Regarding B. subtilis however there was no distinct deviation among the antibacterial activities at different incubation temperatures, as expected from the equal MBC values for coil and globule conformation.…”

Thermo-responsive polymers

“…The reduction in polymer-water hydrogen bonds above LCST leads to the formation of more collapsed and compact-folded globular structures (Alaghemandi & Spohr, 2012;Baltes, Garret-Flaudy, & Freitag, 1999;Deshmukh, Mooney, Mcdermott, Kulkarni, & Macelroy, 2009;Galaev & Mattiasson, 1993). These studies revealed that water-polymer hydrogen bonds around polar groups in polymer chains (-NH in PNIPAAm) play a vital role in polymer-polymer and polymer-water interactions and in the hydration of polymer chains.…”