氘代诱导的聚N-异丙基丙烯酰胺微凝胶的体积相变温度偏移
Deuteration-Induced Volume Phase Transition Temperature Shift of PNIPMAM Microgels.
作者信息
Cors Marian, Wiehemeier Lars, Oberdisse Julian, Hellweg Thomas
机构信息
Department of Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany.
Laboratoire Charles Coulomb (L2C), University of Montpellier, CNRS, 34095 Montpellier, France.
出版信息
Polymers (Basel). 2019 Apr 3;11(4):620. doi: 10.3390/polym11040620.
The effect of deuteration on the volume phase transition (VPT) temperature of poly (-isopropylmethacrylamide) (pNIPMAM) microgels in aqueous suspension is determined via IR spectroscopy and size measurements by photon correlation spectroscopy (PCS). We study the effect of a hydrogenated and a deuterated solvent (H₂O/D₂O), and of the hydrogenated and (partially) deuterated monomer. Deuteration of the monomer or copolymerization with deuterated monomers shifts the volume phase transition temperature (VPTT) by up to 8.4 K to higher temperatures, in good agreement with known results for pNIPAM microgels. Moreover, the shape of the swelling curve is found to depend on deuteration, with the highest deuteration leading to the sharpest VPT. Finally, the quantitative agreement between FTIR spectroscopy and PCS evidences the spatial homogeneity of the microgel particles. Our results are rationalized in terms of the effect of deuteration on hydrogen bonding. They shall be of primary importance for any experimental measurements close to the VPT involving isotopic substitution, and in particular contrast variation small angle neutron scattering.
通过红外光谱法以及光子相关光谱法（PCS）进行尺寸测量，确定了氘代对水悬浮液中聚（甲基丙烯酸异丙酯）（pNIPMAM）微凝胶体积相变（VPT）温度的影响。我们研究了氢化溶剂和氘代溶剂（H₂O/D₂O）以及氢化单体和（部分）氘代单体的影响。单体的氘代或与氘代单体的共聚可使体积相变温度（VPTT）升高多达8.4 K，这与pNIPAM微凝胶的已知结果高度一致。此外，发现溶胀曲线的形状取决于氘代情况，氘代程度最高时导致体积相变最为急剧。最后，傅里叶变换红外光谱法（FTIR）与PCS之间的定量一致性证明了微凝胶颗粒的空间均匀性。我们的结果根据氘代对氢键的影响进行了合理化解释。它们对于任何涉及同位素取代且接近体积相变的实验测量，尤其是对比变化小角中子散射，都具有至关重要的意义。
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