Thermoresponsive dendritic oligoethylene glycols

Abstract

Monodispersed molecules of low molar masses showing thermoresponsiveness are appealing both for mechanism investigation of the thermally-modulated dehydration and aggregation on molecular level and for designing functional intelligent materials. In...

Thermoresponsive Dendronized Microgels through In Situ Cross-Linking Polymerization to Exhibit Enhanced Confinement for Solvatochromic Dyes

“…OEG-based dendronized macromonomers EtG1 - MA and MeG1 - MA carrying ethoxyl and methoxyl terminals, respectively, were prepared according to our previous reports. , The ethoxyl terminals on the OEG dendrons of EtG1 - MA contribute to greater hydrophobicity, while methoxyl terminals in MeG1 - MA are more hydrophilic, resulting in different phase transition temperatures . The thermally mediated aggregation of the two macromonomers to form mesoglobules was examined by turbidimetry and dynamic light scattering (DLS) measurements.…”

“…28,29 The ethoxyl terminals on the OEG dendrons of EtG1-MA contribute to greater hydrophobicity, while methoxyl terminals in MeG1-MA are more hydrophilic, resulting in different phase transition temperatures. 42 The thermally mediated aggregation of the two macromonomers to form mesoglobules was examined by turbidimetry and dynamic light scattering (DLS) measurements. For the more hydrophobic monomer EtG1-MA, the characteristic thermoresponsive behavior was observed, i.e., aggregation at appropriate concentrations to form mesoglobules at elevated temperatures (Figure S1a).…”

“…Through the formation of spherical microgels or hydrogels, these dendronized polymers afford higher-level encapsulation and can protect efficiently guest proteins from denaturation or biodegradation. − Solvation differences during the thermally mediated collapse can modulate the transition of hydrophilic dendritic OEG moieties from the core of the aggregates to their periphery, providing a novel way to transfer encapsulated guests in a well-controlled fashion . More recently, we found that OEG-based dendronized macromonomers themselves exhibit characteristic thermoresponsive behavior, dependent on their overall hydrophilicity, concentration, and branching density (2-fold, 3-fold, 4-fold, and 6-fold) of dendritic OEGs . Preliminary experimental results show that various sizes of mesoglobules can be formed through thermally induced aggregation of these macromonomers, allowing a possible way to transform the aggregated monomers directly to microgels through cross-linking polymerization.…”

“…41 More recently, we found that OEG-based dendronized macromonomers themselves exhibit characteristic thermoresponsive behavior, dependent on their overall hydrophilicity, concentration, and branching density (2-fold, 3-fold, 4-fold, and 6-fold) of dendritic OEGs. 42 Preliminary experimental results show that various sizes of mesoglobules can be formed through thermally induced aggregation of these macromonomers, allowing a possible way to transform the aggregated monomers directly to microgels through crosslinking polymerization. Combining the advantages of dendritic topologies and the thermoresponsive microgels in one matter, we report here on a method for the fabrication of thermoresponsive microgels through in situ polymerization of thermally aggregating the dendronized macromonomers at elevated temperatures.…”

Thermoresponsive Helical Dendronized Poly(phenylacetylene)s: Remarkable Stabilization of Their Helicity via Photo-Dimerization of the Dendritic Pendants

“…In other words, dendronized macromonomers tend to form head-to-head dimerization through photodimerization, which may be attributed to their intrinsic amphiphilicities in aqueous solutions. 68 Subsequently, photoirradiation of the dendronized PPAs was performed in their dilute aqueous solutions (< 2 mg mL −1 ) at room temperature, aiming at intramolecular photocycloaddition. UV/vis spectra of the polymers Et=PPA and Me=PPA after irradiation for different time durations are shown in Figures 3a and S27a, respectively.…”