Rapid Phase Separation in Aqueous Solution of Temperature‐Sensitive Poly(N,N‐diethylacrylamide)

Abstract

The dynamic phase separation behavior in aqueous solutions of poly(N,N‐diethylacrylamide) (PDEA), which is a representative thermoresponsive polymer, is studied using a laser temperature‐jump technique combined with transient photometry, with which the time constant for phase separation can be determined. Two components of the time constant (τfast and τslow) are clearly observed irrespective of the polymer concentration or molecular weight of the PDEA. Such a fast phase separation component (τfast) has never been observed in poly(N‐isopropylacrylamide) (PNIPAM) systems. Furthermore, the slow phase separation process of PDEA is faster than that in a PNIPAM system. It is shown that the fast phase separation process for PDEA originates from polymer aggregates formed even below the cloud point. The phase separation mechanism of PDEA is similar to that of poly (alkyl vinyl ether), rather than PNIPAM.

Design and synthesis study of the thermo‐sensitive copolymer carrier of penicillin G acylase

“…However, due to its poor biocompatibility and low LCST, it has seriously affected its future application prospects. Recent studies have shown that the biocompatibility of poly ( N N ‐diethylacrylamide) (PDEA) is far superior to that of PNIPAM, and its LCST is also higher than that of PNIPAM. If thermo‐sensitive block copolymer with suitable LCST could be used as carrier to the immobilization of PGA, the carrier would realize the aim that the immobilization and catalyzation would be conducted at solution state, while the recovery would be carried out under its gelatin state.…”

Dynamics of the Phase Separation in a Thermoresponsive Polymer: Accelerated Phase Separation of Stereocontrolled Poly(N,N-diethylacrylamide) in Water

“…43 chains. 40 The average value of d H for Peak-I increases from 10 nm to 19 nm with increasing isotacticity. This suggests that individual PDEA chains with higher isotacticity have relatively loose structures below T c due to the sufficiently high level of hydration (higher hydrophilicity) compared with the lower isotacticity sample, which is in good agreement with the effect of the tacticity on T c .…”

“…In our previous study, we determined time constants of the phase separation for atactic PDEA and revealed that PDEA had two phase separation processes: a fast and a slow process. 40 We briefly describe the phase separation mechanism as follows. In the slow phase separation process, individual polymer chains (polymer globules) aggregate with each other by diffusion in solution.…”

“…The cloud point (T c ) of the sample solutions was determined on the basis of the temperature dependence of the optical transmittance. 40 Temperature-variable dynamic light scattering (DLS) by the sample solutions (0.10 wt%) was measured using an ELSZ-2000ZS (Otsuka Electronics Co.). The sample solutions were filtered (Advantec, 13CP045AS, pore size: 0.45 μm) before the DLS experiments.…”

“…39 In a previous study we showed that the phase separation for PDEA is much faster than that for PNIPAM, and the phase separation mechanism for PDEA is partly different from that for PNIPAM. 40 Such obvious differences between PNIPAM and PDEA are due to interactions between the side chains and water molecules and/or between the side chains themselves (hydrophobic interaction). 41 In the present study, we focused on the tacticity of PDEA.…”