Dresden 2014 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 54: Poster Session 3

CPP 54.56: Poster

Thursday, April 3, 2014, 15:00–19:00, P2

molecular dynamics simulation of the LCST shifting of modified PNIPAM — •Yongbiao Yang¹, Ganesh Balasubramanian², Michael Böhm¹, and Florian Müller-plathe¹ — ¹Alarich-Weiss-Str. 4 64287 Darmstadt — ²Iowa State University Ames, IA 50011, USA

The local conformation of chemical systems containing photo-responsive units such as spiropyran and merocyanine can be changed by light radiation of suitable wave length. Such photo-responsive units can be added to polymer chains which then become photo-responsive, too. As a result, the functionalized polymers can exhibit reversible functionalities. Poly(N-isopropylacrylamide) (PNIPAM) is a intensively used temperature-responsive polymer with the lower critical solution temperature (LCST) of 305 K. By grafting with merocyanine or spiropyran units, LCST of PNIPAM is expected to be changed. In our simulations, the temperature-responsive behaviour of modified PNIPAM is studied by using molecular dynamics simulations. All-atom models of modified PNIPAM in solution are built based on the parameters obtained from density functional calculations, and molecular dynamics simulations are performed for systems including a single polymer chain. The LCST of PNIPAM is found to be shifted after grafting photo-responsive units. But the influence of merocyanine and spiropyran units are very different. This originates from their different local structures according to our density functional calculations.