Dynamics in Stimuli-Responsive Poly(N-isopropylacrylamide) Hydrogel Layers As Revealed by Fluorescence Correlation Spectroscopy

Abstract

Experimental sectionFigure.S1. Normalized fluorescence intensity profile, I F (z)/I F,max , for A488 in HG-6 (white) and in the supernatant solution (grey) vs. distance z normal to the substrate (grey), at different ionic strength (I) values of a monovalent salt (KNO 3 ) , at 25°C. The grey highlighted regions denote the bounds of the fully swollen HG thickness at each I value.Interpretation of the z-scans: For the fitting procedure, we consider a gel grafted on a glass slide such that the glass-gel interface spans the xy plane and z is the direction normal to the xy plane. We further assume that the interface between the gel and the glass slide is located at z = A and the interface between the gel and the supernatant solution is located at z = B. We further assume that the tracer concentration

Dynamic Response of Anchored Poly(N‐isopropylacrylamide‐co‐methacrylic acid‐co‐benzophenone methacrylate) Terpolymer Hydrogel Layers to Physicochemical Stimuli

“…Interestingly, similar trend was observed for the amplitude of the slow molecular tracer diffusion in the same PNIPPAM hydrogel layers upon adding monovalent salt. The slow tracer diffusion is associated with a dynamic arrest in the dense (collapsed) domain …”

“…The slow tracer diffusion is associated with a dynamic arrest in the dense (collapsed) domain. [ 44 ]…”

Diffusive properties of solvent molecules in the neighborhood of a polymer chain as seen by Monte-Carlo simulations

“…In consequence, many polymer systems (concentrated solutions, membranes, gels) deviate from normal (Fickian) diffusion. [1][2][3][4][5][6][7] Diffusion is an especially important issue in stimuli responsive gels exhibiting volume phase transition (VPT). In such systems, molecular mobility (diffusivity in the case of water and molecular relaxations of polymer segments) is one of the key factors that determine dynamics of VPT.…”

Transport in PEG‐Based Hydrogels: Role of Water Content at Synthesis and Crosslinker Molecular Weight

“…Fluorescence correlation spectroscopy (FCS) has been previously shown effective to measure in situ transport properties of small molecules in various polymeric systems . This includes the use of FCS to examine the diffusion of probe molecules in hydrogels . It has been shown that higher molar ratios of chemical crosslinkers lead to slower diffusion of probe molecules .…”

“…[21][22][23][24] This includes the use of FCS to examine the diffusion of probe molecules in hydrogels. [17,[25][26][27][28][29] It has been shown that higher molar ratios of chemical crosslinkers lead to slower diffusion of probe molecules. [30] Less studied are the effects of water content during hydrogel synthesis on the transport properties of probe molecules.…”