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. 2018 Aug 2;10(8):858.
doi: 10.3390/polym10080858.

Synthesis of Poly(ε-caprolactone)-Based Miktoarm Star Copolymers through ROP, SA ATRC, and ATRP

Venkatesan Sathesh  1 , Jem-Kun Chen  2 , Chi-Jung Chang  3 , Junko Aimi  4 , Zong-Cheng Chen  5 , Yu-Chih Hsu  6 , Yi-Shen Huang  7 , Chih-Feng Huang  8   9
Affiliations

Synthesis of Poly(ε-caprolactone)-Based Miktoarm Star Copolymers through ROP, SA ATRC, and ATRP

Venkatesan Sathesh et al. Polymers (Basel). .

Abstract

The synthesis of novel branched/star copolymers which possess unique physical properties is highly desirable. Herein, a novel strategy was demonstrated to synthesize poly(ε-caprolactone) (PCL) based miktoarm star (μ-star) copolymers by combining ring-opening polymerization (ROP), styrenics-assisted atom transfer radical coupling (SA ATRC), and atom transfer radical polymerization (ATRP). From the analyses of gel permeation chromatography (GPC), proton nuclear magnetic resonance (¹H NMR), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), well-defined PCL-μ-PSt (PSt: polystyrene), and PCL-μ-PtBA (PtBA: poly(tert-butyl acrylate) μ-star copolymers were successfully obtained. By using atomic force microscopy (AFM), interestingly, our preliminary examinations of the μ-star copolymers showed a spherical structure with diameters of ca. 250 and 45 nm, respectively. We successfully employed combinations of synthetic techniques including ROP, SA ATRC, and ATRP with high effectiveness to synthesize PCL-based μ-star copolymers.

Keywords: atom transfer radical polymerization; miktoarm star copolymers; ring-opening polymerization; styrenics-assisted atom transfer radical coupling.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
Synthetic routes of poly(ε-caprolactone)-based μ-star copolymers.
Figure 1
Figure 1
GPC traces (RI detector) of (a) PCL–OH, (b) PCL–Br, and (c) PCL-VBCm-PCL.
Figure 2
Figure 2
1H NMR spectra (400 MHz, CDCl3) of (a) PCL–OH, (b) PCL–Br, and (c) PCL-VBCm-PCL.
Figure 3
Figure 3
MALDI-TOF MS of (a) PCL–Br and (b) PCL-VBCm-PCL polymers (n: repeating units of CL).
Figure 4
Figure 4
Chain extension of PCL-VBC4-PCL with St of (A) kinetic plots and (B) GPC traces (eluent: THF).
Figure 5
Figure 5
Chain extension of PCL-VBC4-PCL with tBA of (A) kinetic plots and (B) GPC traces (eluent: THF).
Figure 6
Figure 6
1H NMR spectra (400 MHz, CDCl3) of (a) PCL-VBCm-PCL, (b) PCL-μ-PSt, and (c) PCL-μ-PtBA (co)polymers.
Figure 7
Figure 7
DSC traces of (a,b) PCL-μ-PSt and (c,d) PCL-μ-PtBA star copolymers (a,c: first run and b,d: second run).
Figure 8
Figure 8
TGA (A) and DTGA (B) traces of (a) PCL-μ-PSt and (b) PCL-μ-PtBA star copolymers.
Figure 9
Figure 9
AFM images of (a) PCL and (b) PCL-μ-PSt (co)polymers (H: height and P: phase).
Figure 10
Figure 10
AFM images of (a) PCL-μ-PtBA and (b) PCL-μ-PAA star copolymers (H: height and P: phase).
Figure 11
Figure 11
Proposed self-assembled microstructures of μ-star copolymers: schematic representation of (A) self-assembled microstructure from immiscible segments and (B) homogeneous surface from miscible segments.
See this image and copyright information in PMC

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