Swelling behaviour of core–shell microgels in H₂O, analysed by temperature-dependent FTIR spectroscopy

Abstract

The structural basis for linear thermoresponses of smart core–shell microgels is elucidated by FTIR spectroscopy, being sensitive to core processes.

Deuteration-Induced Volume Phase Transition Temperature Shift of PNIPMAM Microgels

“…This allows gathering of information on the particle architecture. As shown before [53], a statistical co-polymerization leads to only one phase transition in FTIR, whereas larger homo-polymer domains and gradients in composition result in separated phase transitions or a broadened phase transition compared to the homo-polymers, respectively.…”

“…In a previous study we applied temperature dependent FTIR-spectroscopy of the NH-band as a direct probe for the hydrogen bonding. Moreover, we established IR-spectroscopy to study co-polymer microgels [53]. In this work, we aim to apply FTIR spectroscopy of microgels in D 2 O [66,67,68] to ensure that the hydrogenated and deuterated monomers copolymerize in a statistical manner on the molecular level.…”

“…We have recently described the procedure of Fourier transform infrared (FTIR) spectroscopy of microgels in a dedicated article [53]. In short, the used FTIR spectrometer (Tensor 27, Bruker, Billerica, MA, USA) was controlled with OPUS 7.5 (Bruker, Billerica, MA, USA).…”

Contrast variation SANS measurement of shell monomer density profiles of smart core–shell microgels

“…24 Combining two monomers of different transition temperatures in statistical copolymers can be used to tune the swelling transition temperature, [25][26][27][28][29] whereas the subsequent synthesis of core and then shell 27,30-35 may lead to a continuous, linear temperature dependent swelling. 27,36,37 The linearity of the response of these coreshell systems might be beneficial especially for sensors and actuators. An explanation of the restricted swelling of the core in the linear regime has been proposed and termed the "corset effect".…”

Resolving the internal morphology of core–shell microgels with super-resolution fluorescence microscopy

“…Instead both materials interpenetrate to a large degree. 16,17 Recently, advances were made in the visualization of microgel morphology by using super-resolution uorescence microscopy, which circumvents the optical diffraction limit. 18,19 Single molecule localization based microscopy methods such as photoactivation localization microscopy (PALM), 20 direct stochastical optical reconstruction microscopy (dSTORM) 21 or point accumulation for imaging in nanoscale topography (PAINT) [22][23][24] were used for this purpose.…”