Tuning the Phase Transition from UCST‐Type to LCST‐Type by Composition Variation of Polymethacrylamide Polymers,Macromolecular Rapid Communications

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Tuning the Phase Transition from UCST‐Type to LCST‐Type by Composition Variation of Polymethacrylamide Polymers
Macromolecular Rapid Communications ( IF 4.2 ) Pub Date : 2018-10-03 , DOI: 10.1002/marc.201800640
Florian Käfer ₁ , Martin Pretscher ₁ , Seema Agarwal ₁

Affiliation

Polymethacrylamide copolymers with hydrophobic N‐substituted acrylamides, such as N‐cyclohexylacrylamide and N‐tert‐butylacrylamide, are rare examples of polymers showing composition‐dependent thermoresponsive behavior in water. They show unexpected behavior different from the conventional copolymers of a thermoresponsive polymer with hydrophobic comonomers. On increasing the amount of the hydrophobic comonomer in the polymer, there is a change from UCST‐type phase behavior to complete solubility, followed by compositions showing LCST‐type transition and insolubility in water (U‐S‐L‐I‐type change). At 50 mol% of less hydrophobic N‐tert‐butyl acrylamide (logP 0.87) in contrast to ≈25 mol% of N‐cyclohexylacrylamide (logP 1.51), the broad UCST‐type transition of polymethacrylamide is turned to LCST‐type transitions with very narrow hysteresis in water and PBS buffer. The use of H‐bond and water‐structure breaker showed the role of H‐bonding and hydrophobic interactions in phase transitions of UCST‐type and LCST‐type, respectively. This work is an important add‐on to the infant field of nonionic polymers of UCST‐type.

中文翻译：

通过改变聚甲基丙烯酰胺聚合物的组成来调节从UCST型到LCST型的相变

具有疏水性N-取代的丙烯酰胺的聚甲基丙烯酰胺共聚物，例如N-环己基丙烯酰胺和N-叔丁基丙烯酰胺，是在水中表现出成分依赖性热响应性的聚合物的稀有例子。它们显示出与热响应性聚合物与疏水性共聚单体的常规共聚物不同的出乎意料的行为。随着聚合物中疏水性共聚单体数量的增加，从UCST型相行为转变为完全溶解性，随后组成表现出LCST型转变和在水中的不溶性（U‐S‐L‐I型变化）。在50摩尔％以下的疏水性ñ -叔丁基丙烯酰胺（0.87的logP）在对比≈25％（摩尔）的Ñ环己基丙烯酰胺（logP 1.51），聚甲基丙烯酰胺的广泛UCST型转变转变为LCST型转变，在水和PBS缓冲液中的滞后非常窄。H键和水结构破坏剂的使用分别显示了H键和疏水相互作用在UCST型和LCST型的相变中的作用。这项工作是UCST型非离子聚合物婴儿领域的重要补充。

更新日期：2018-10-03

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