Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
Helmholtz-Zentrum Berlin (HZB), Hanhn-Meitner-Platz 1, 14109 Berlin, Germany.
Soft Matter. 2017 Jan 18;13(3):658-669. doi: 10.1039/c6sm02262f.
An UCST-type copolymer of acrylamide (AAm) and acrylonitrile (AN) (poly(AAm-co-AN)) was prepared by reversible addition fragmentation chain transfer (RAFT) polymerization and its temperature-induced phase transition and aggregation behaviour studied by turbidimetry, static and dynamic light scattering, small angle neutron scattering (SANS) and cryo-transmission electron microscopy (cryo-TEM) measurements. The phase transition temperature was found to increase with increasing AN content in the copolymer, concentration of the solutions and copolymer chain length. A significant effect was observed onto the phase transition temperature by addition of different electrolytes into the copolymer solution. The copolymer chains were aggregated below the phase transition temperature and disaggregated above it. The size of the aggregates increases with increasing AN contents and concentration of the copolymer solutions below the phase transition temperature. The copolymer chains were expanded and weekly associated in solution above the phase transition temperature. A model is proposed to explain such association-aggregation behaviour of poly(AAm-co-AN) copolymers depending on AN contents and concentration of the copolymer solutions as a function of temperature.
一种由丙烯酰胺（AAm）和丙烯腈（AN）组成的 UCST 型共聚物（poly(AAm-co-AN)）通过可逆加成断裂链转移（RAFT）聚合制备，并通过浊度法、静态和动态光散射、小角中子散射（SANS）和低温透射电子显微镜（cryo-TEM）测量研究其温度诱导的相转变和聚集行为。发现相转变温度随共聚物中 AN 含量、溶液浓度和共聚物链长的增加而升高。向共聚物溶液中加入不同的电解质对相转变温度有显著影响。共聚物链在相转变温度以下聚集，在相转变温度以上解聚。在相转变温度以下，随着 AN 含量和共聚物溶液浓度的增加，聚集物的尺寸增大。提出了一个模型来解释聚（AAm-co-AN）共聚物的这种依赖于 AN 含量和共聚物溶液浓度作为温度函数的缔合-聚集行为。
