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Molecular Dynamics Investigation of the Thermo‐Responsive Polymer Poly( N ‐isopropylacrylamide)
Author(s) -
Alaghemandi Mohammad,
Spohr Eckhard
Publication year - 2012
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/mats.201100071
Subject(s) - lower critical solution temperature , molecular dynamics , polymer , poly(n isopropylacrylamide) , monomer , chain (unit) , chemical physics , thermodynamics , chemistry , materials science , polymer chemistry , statistical physics , physics , copolymer , computational chemistry , organic chemistry , astronomy
Using molecular dynamics simulations with an OPLS force field, the lower critical solution temperature (LCST) of single‐ and multiple‐chain PNIPAM solutions in water is investigated. The sample containing ten polymer chains shows a sudden drop in size and volume at 305 K. Such an effect is absent in the single‐chain system. Large fluctuations of the physical properties of a short single‐chain prevent any clear detection of the LCST for the chosen model system, at least on the time scale of 200 ns. The results provide evidence that a critical number of PNIPAM monomer units must be present in the simulated system before MD simulations are capable to detect conformational changes unambiguously.