Poly-Nisopropylacrylamide (PNIPAM) is a thermo-responsive polymer that has attracted considerable attention as a “smart” material with a wide variety of applications, ranging from drug delivery to sensors. PNIPAM microgels can be synthetized by copolymerizing the NIPAM monomer with bisacrylamide (BIS). The resulting structure is characterized by cross-linked networks that swell in water at room temperature giving rise to transparent gels. Nowadays it is well recognized that water has a strong influence on the structural and dynamical behavior of molecules and macromolecules. Hydration plays an important role in stabilizing many aqueous systems. Investigations of the dynamics of the hydrating water molecules are therefore crucial to understand the phase behavior of polymer aqueous solutions. In the present work the structural and dynamical properties of PNIPAM microgels and the polymer- induced water properties variations have been investigated upon cooling by means of molecular dynamics simulations. The PNIPAM network model was built taking into account the inhomogeneous polymer radial density within the microgel, on the basis of the value of the PNIPAM repeating units/bis-acrylamide mole ratio, PNIPAM/BIS, used during the synthesis and of the maximum degree of swelling of such microparticle. The computational methodology was based on previous atomistic modelling studies that characterized the PNIPAM behavior in aqueous solution [1,2]. A description of the water and PNIPAM dynamics at low temperatures will be presented for microgel systems at di↵erent hydration levels and compared to recent neutron scattering experiments [3].
Chiessi, E., Tavagnacco, L., Zaccarelli, E. (2017). Hydration water in PNIPAM microgels: a molecular dynamics simulation study at low temperatures. In Book of Abstracts (pp.63-63). Rome.
Hydration water in PNIPAM microgels: a molecular dynamics simulation study at low temperatures
CHIESSI, ESTER;
2017-06-16
Abstract
Poly-Nisopropylacrylamide (PNIPAM) is a thermo-responsive polymer that has attracted considerable attention as a “smart” material with a wide variety of applications, ranging from drug delivery to sensors. PNIPAM microgels can be synthetized by copolymerizing the NIPAM monomer with bisacrylamide (BIS). The resulting structure is characterized by cross-linked networks that swell in water at room temperature giving rise to transparent gels. Nowadays it is well recognized that water has a strong influence on the structural and dynamical behavior of molecules and macromolecules. Hydration plays an important role in stabilizing many aqueous systems. Investigations of the dynamics of the hydrating water molecules are therefore crucial to understand the phase behavior of polymer aqueous solutions. In the present work the structural and dynamical properties of PNIPAM microgels and the polymer- induced water properties variations have been investigated upon cooling by means of molecular dynamics simulations. The PNIPAM network model was built taking into account the inhomogeneous polymer radial density within the microgel, on the basis of the value of the PNIPAM repeating units/bis-acrylamide mole ratio, PNIPAM/BIS, used during the synthesis and of the maximum degree of swelling of such microparticle. The computational methodology was based on previous atomistic modelling studies that characterized the PNIPAM behavior in aqueous solution [1,2]. A description of the water and PNIPAM dynamics at low temperatures will be presented for microgel systems at di↵erent hydration levels and compared to recent neutron scattering experiments [3].I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
