Synthesis, characterization, electrochromic properties, and electrochromic device application of a novel star polymer consisting of thiophene end‐capped poly(ε‐caprolactone) arms emanating from a hexafunctional cyclotriphosphazene core

Abstract

Hexa‐armed and thiophene (Thi) end‐capped poly(ε‐caprolactone) star polymer (N3P3‐(PCL‐Thi)6), containing cyclotriphosphazene core, was prepared in a four‐step reaction sequence. Ring‐opening polymerization (ROP) and “click chemistry” techniques were employed in the first and final steps, respectively. Hexa‐armed PCL star polymer (N3P3‐(PCL‐OH)6) was successfully synthesized via ROP of ε‐caprolactone (ε‐CL) by using hekzakis(p‐(hydroxymethyl)phenoxy) cyclotriphosphazene as the multisite initiator and tin(II) 2‐ethylhexanoate (Sn(Oct2)) as the catalyst in bulk at 115 °C. Further modifications of the N3P3‐(PCL‐OH)6 were accomplished by derivatization of the hydroxyl‐functional chain ends. The obtained N3P3‐(PCL‐OH)6 was then reacted with 2‐bromo‐2‐methylpropanoyl bromide, and this led to a star polymer with bromide end groups, N3P3‐(PCL‐Br)6. In the third step, N3P3‐(PCL‐Br)6 was azidified with sodium azide (NaN3) in DMF affording N3P3‐(PCL‐N3)6. Conversion of the azide chain end groups into Thi was quantitatively accomplished via the “click reaction” between N3P3‐(PCL‐N3)6 and prop‐2‐yn‐1‐yl 3‐thienyl acetate in the final step. Subsequently, the star polymer with six Thi chain ends (N3P3‐(PCL‐Thi)6) was employed in electrochemical copolymerization with both pyrrole and Thi. Electrochromic properties and electrochromic device application of N3P3‐(PCL‐Thi)6/PThi were also investigated. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3668–3682, 2010

Synthesis, characterization, and Pb2+ ion sensing application of hexa‐armed dansyl end‐capped poly(ε‐caprolactone) star polymer with phosphazene core

“…30 Liu and coworkers prepared dansyl-labeled poly(N-isopropylacrylamide) microgels to be used as fluorescent Cu 21 sensor and showed that thermo-induced collapse of the sensing material remarkably increased its detection sensitivity. 34 Phosphonitrilic trimer derivatives having proper functional groups have been employed as the connecting (core) unit for the preparation of star-shaped polymers via corefirst (divergent) 35,36 and arm-first (convergent) approaches. 32,33 They have less entanglement in the solid state, high solubility in various organic solvents, as well as lower solution and bulk viscosities compared to linear ones having similar molecular weights.…”

Pyrene‐functional star polymers as fluorescent probes for nitrophenolic compounds

“…In this manner, azide functional units of (S1‐S3)‐N 3 were reacted with alkyne unit of 1‐ethynylpyrene, providing pyrene‐functional styrenic star copolymers [ (S1‐S3)‐Pyr ]. Click reactions have considerably high compatibility to various functional units and solvents and give regiospecific 1,3‐cycloaddition products with near quantitative yields under mild reaction conditions …”

NITROAROMATIC COMPOUND SENSING APPLICATION OF HEXA-ARMED DANSYL END-CAPPED POLY(epsilon-CAPROLACTONE) STAR POLYMER WITH PHOSPHAZENE CORE

“…Star-shaped polymers consist of several linear chains connected to a central core and have many advantages due to their compact molecular shapes, highly branched structures and unique rheological properties [24][25][26][27][28][29][30][31][32][33][34]. They are highly soluble in organic solvents, have smaller hydrodynamic volume and radius of gyration, resulting in their lower solution and melt viscosities with respect to linear polymers with similar molecular weights [32].…”