Dynamic Fluctuations of Thermoresponsive Poly(oligo-ethylene glycol methyl ether methacrylate)-Based Hydrogels Investigated by Dynamic Light Scattering

Abstract

The dynamics of thermoresponsive and biocompatible gels was investigated using dynamic light scattering. The gels were copolymerized by two types of ethylene glycol methacrylates having short and long hydrophilic side chains consisting of ethylene oxide units. Their dynamics was decomposed to fast and slow modes. The critical temperature was determined from the fast mode (cooperative diffusion) and was controlled lineally by the copolymerization ratio of the two monomers, which is one of the advantages in the gel system. The formation mechanism of hydrophobic domains in the gels was investigated from the slow mode. The hydrophobic domains grew in the gels by rising temperature, and they were copolymerization ratio dependent. The domain formation was suppressed as the copolymerization ratio of the longer side chain was increased. The results of this study should lead to new design strategy for the bioapplications, including drug delivery systems that require a retention of their smart functions.

Fast Switching of Bright Whiteness in Channeled Hydrogel Networks

“…However, these samples did not show significantly enhanced whiteness compared to the channeled hydrogel using agarose (Figure S6, Supporting Information). On the other hand, agarose can be used to prepare channeled networks with other LCST hydrogels, such as P(DEGMA‐co‐OEGMA), [ 39 ] or poly( N ‐vinylcaprolactam) [ 40 ] as the second crosslinked network, which all show enhanced whiteness above the LCST compared to pure hydrogels (Figure S7, Supporting Information). Together with the fact that the reflectance of the hydrogel is much lower if the agarose is not gelled before the polymerization of the PNIPAm network (Figure S8, Supporting Information), it can be proposed that the percolated agarose network serves as a physical template and modifies the microscopic structure of the second hydrogel network by introducing nanoscopic channels, which lead to the enhanced whiteness of the PNIPAm network above the LCST without affecting much the transparency at room temperature.…”

Injectable Hydrogels: From Laboratory to Industrialization

“…Dynamic light scattering (DLS) is a technique from which lots of parameters and properties from the polymeric systems can be obtained, such as molecular distribution, particle size distribution, molecular weight of the polymer, molecular weight distribution, polydispersity index, hydrodynamic size, shape, structure, aggregation state, and biomolecule conformation, among others [ 53 ]. Moreover, it possesses several advantages as it is noninvasive, has high accuracy and reproducible measurements, short experiment times (minutes), and low apparatus costs.…”

Chemically Responsive Hydrogel Deformation Mechanics: A Review

“…Nonetheless, this study provided the framework for future studies on capturing the transient swelling of hydrogels. Furthermore, advances of Dynamic Light Scattering (DLS) used to probe the diffusion of particles has allowed for the quantification of the transient properties of polymer chains at a microscopic level, providing a better understanding of the rheology of the system [98,99]. With recent advances in imaging capabilities, mostly as a result of the need for CMOS image sensors in the mobile phone industry, there exist several potential systems for this application [100,101].…”