Synthesis and Characterization of a Thermoresponsive Copolymer with an LCST-UCST-like Behavior and Exhibiting Crystallization
(2023) In ACS Omega 8(34). p.31145-31154- Abstract
In this work, the diblock copolymer methoxy-poly(ethylene glycol)-block-poly(ϵ-caprolactone) (MPEG-b-PCL) was synthesized with a block composition that allows this polymer in aqueous media to possess both an upper critical solution temperature (UCST) and a lower critical solution temperature (LCST) over a limited temperature interval. The value of the UCST, associated with crystallization of the PCL-block, depended on heating (H) or cooling (C) of the sample and was found to be CPUCSTH = 32 °C and CPUCSTC = 23 °C, respectively. The LCST was not affected by the heating or cooling scans; assumed a value of 52 °C (CPLCSTH = CPLCSTC). At intermediate... (More)
In this work, the diblock copolymer methoxy-poly(ethylene glycol)-block-poly(ϵ-caprolactone) (MPEG-b-PCL) was synthesized with a block composition that allows this polymer in aqueous media to possess both an upper critical solution temperature (UCST) and a lower critical solution temperature (LCST) over a limited temperature interval. The value of the UCST, associated with crystallization of the PCL-block, depended on heating (H) or cooling (C) of the sample and was found to be CPUCSTH = 32 °C and CPUCSTC = 23 °C, respectively. The LCST was not affected by the heating or cooling scans; assumed a value of 52 °C (CPLCSTH = CPLCSTC). At intermediate temperatures (e.g., 45 °C), dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM) showed that the solution consisted of a large population of spherical core-shell particles and some self-assembled rodlike objects. At low temperatures (below 32 °C), differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) in combination with SAXS disclosed the formation of crystals with a cylindrical core-shell structure. Cryo-TEM supported a thread-like appearance of the self-assembled polymer chains. At temperatures above 52 °C, incipient phase separation took place and large aggregation complexes of amorphous morphology were formed. This work provides insight into the intricate interplay between UCST and LCST and the type of structures formed at these conditions in aqueous solutions of MPEG-b-PCL diblock copolymers.
(Less)
- author
- Gjerde, Natalie Solfrid ; Del Giudice, Alessandra LU ; Zhu, Kaizheng ; Knudsen, Kenneth D. ; Galantini, Luciano LU ; Schillén, Karin LU and Nyström, Bo
- organization
- publishing date
- 2023-08-17
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Copolymers, Crystallization, Crystals, Micelles, X-ray scattering
- in
- ACS Omega
- volume
- 8
- issue
- 34
- pages
- 31145 - 31154
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- pmid:37663484
- scopus:85169057574
- ISSN
- 2470-1343
- DOI
- 10.1021/acsomega.3c03162
- language
- English
- LU publication?
- yes
- id
- cb7b6f0c-20b1-4e6a-b80a-01054e8d93b7
- date added to LUP
- 2023-09-14 11:00:47
- date last changed
- 2024-04-20 03:15:14
@article{cb7b6f0c-20b1-4e6a-b80a-01054e8d93b7, abstract = {{<p>In this work, the diblock copolymer methoxy-poly(ethylene glycol)-block-poly(ϵ-caprolactone) (MPEG-b-PCL) was synthesized with a block composition that allows this polymer in aqueous media to possess both an upper critical solution temperature (UCST) and a lower critical solution temperature (LCST) over a limited temperature interval. The value of the UCST, associated with crystallization of the PCL-block, depended on heating (H) or cooling (C) of the sample and was found to be CP<sub>UCST</sub><sup>H</sup> = 32 °C and CP<sub>UCST</sub><sup>C</sup> = 23 °C, respectively. The LCST was not affected by the heating or cooling scans; assumed a value of 52 °C (CP<sub>LCST</sub><sup>H</sup> = CP<sub>LCST</sub><sup>C</sup>). At intermediate temperatures (e.g., 45 °C), dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM) showed that the solution consisted of a large population of spherical core-shell particles and some self-assembled rodlike objects. At low temperatures (below 32 °C), differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) in combination with SAXS disclosed the formation of crystals with a cylindrical core-shell structure. Cryo-TEM supported a thread-like appearance of the self-assembled polymer chains. At temperatures above 52 °C, incipient phase separation took place and large aggregation complexes of amorphous morphology were formed. This work provides insight into the intricate interplay between UCST and LCST and the type of structures formed at these conditions in aqueous solutions of MPEG-b-PCL diblock copolymers.</p>}}, author = {{Gjerde, Natalie Solfrid and Del Giudice, Alessandra and Zhu, Kaizheng and Knudsen, Kenneth D. and Galantini, Luciano and Schillén, Karin and Nyström, Bo}}, issn = {{2470-1343}}, keywords = {{Copolymers; Crystallization; Crystals; Micelles; X-ray scattering}}, language = {{eng}}, month = {{08}}, number = {{34}}, pages = {{31145--31154}}, publisher = {{The American Chemical Society (ACS)}}, series = {{ACS Omega}}, title = {{Synthesis and Characterization of a Thermoresponsive Copolymer with an LCST-UCST-like Behavior and Exhibiting Crystallization}}, url = {{http://dx.doi.org/10.1021/acsomega.3c03162}}, doi = {{10.1021/acsomega.3c03162}}, volume = {{8}}, year = {{2023}}, }