Organocatalytic Approach to Functional Semifluorinated Polymers Driven by Visible Light

Abstract

Through the construction of an organic photocatalysis system, photoredox catalyst (PC)/additive, where PC stands for photoredox catalyst, an organocatalyzed step transfer-addition and radical-termination (O-START) polymerization irradiated by blue LED light at room temperature is realized. Different types of α,ω-diiodoperfluoroalkane A and α,ω-unconjugated diene B are copolymerized through O-START efficiently, and generate various kinds of functional semifluorinated polymers, including polyolefins and polyesters. The process is affected by several factors; solvents, additives, and feed ratio of A to B. After optimization of all these components, the polymerization efficiency is greatly improved, generating polymers with both relatively high yield and molecular weight. Considering the mild reaction condition, easy operation process, and free-of-metal-catalyst residues in the polymer product, the organocatalytic polymerization strategy provides a simple and efficient approach to functional semifluorinated polymer materials and hopefully opens up their application in high-tech fields.

Hierarchical Self‐Assembly of Triphilic Main‐Chain‐Type Semifluorinated Alternating Graft Copolymers in Aqueous Solution

“…The semifluorinated alternating copolymers (AB) n A were synthesized by our reported method (Table S1, Supporting Information). [ 7a ] Taking (A 2 B 1 ) n A 2 as an example, the [A] 0 :[B] 0 feed ratio was set to 1.2:1 in all cases to ensure that the end groups of (A 2 B 1 ) n A 2 were ended with ‐CF 2 CF 2 H, which could also be verified by 1 H NMR and 19 F NMR spectra (Figure S1, Supporting Information). Substitution reactions of iodine‐containing copolymer (A 2 B 1 ) n A 2 were conducted in CHCl 3 with NaN 3 and phase‐transfer catalyst 18‐ crown ‐6 [ 8b,13 ] and the results were shown in Table S2 (Supporting Information).…”

“…Herein, main‐chain‐type semifluorinated alternating copolymers ((AB) n A, where A represents α , ω ‐diiodoperfluoroalkane and B represents α , ω ‐unconjugated diene) were synthesized by step transfer‐addition and radical‐termination (START) polymerization [ 7 ] and monodisperse methoxy oligo(ethylene glycol)s (mOEG x , x = 3, 6, 9, or 22) side chains could be introduced into the semifluorinated alternating copolymers via mild azide‐alkyne click chemistry [ 8 ] from the periodic CI bonds in the backbone of (AB) n A ( Scheme ). Different from the graft copolymers based on the traditional fluorinated graft copolymers with the backbone such as polyvinylidene fluoride or polychlorotrifluoroethylene , [ 9 ] the final fluorinated graft copolymers (AB) n A‐ g ‐mOEG x could be designed as diverse structures since the structure of the main‐chain type semifluorinated (AB) n A is with powerful designability.…”

RAFT Polymerization of Semifluorinated Monomers Mediated by a NIR Fluorinated Photocatalyst

“…Since the traditional radical polymerization method could not allow the PFs with desired performances, controlled/living radical polymerizations (CRP) have brought a bright direction for fabricating well-defined PFs with superior functionalities. Many CRP approaches, [8][9][10][11][12][13][14] such as atom transfer radical polymerization (ATRP), [15] Lewis pair polymerization (LPP), [16] nitroxide-mediated radical polymerization DOI: 10.1002/marc.202200122 (NMP), [17] and reversible additionfragmentation chain transfer (RAFT) polymerization, [11,12] have been developed to synthesize PFs. Among them, photoinduced CRP, as its features of good control over monomers and friendliness to the environment, has been achieved much attention recently, [18][19][20][21][22][23] and been used to prepare well-defined PFs.…”

Synthesis and Phase Behavior of (Semifluorinated Alkane)‐Based Side‐Chain Liquid Crystalline Copolymers

“…Recently, Kappe et al [39] reported an efficient method for the iodoperfluoroalkylation of alkenes using triethylamine (TEA) additive under short-wavelength purple-light irradiation (405 nm). Also, Cheng et al [40][41][42] developed a photoinduced Step Transfer-Addition & Radical-Termination (START) polymerization to synthesize alternating semifluorinated copolymers (AB) n where A and B were 𝛼,𝜔-diiodoperfluoroalkanes and 𝛼,𝜔-unconjugated dienes, respectively. Inspired by the two efficient methods, in this work, monomer B was designed as a T-shaped structure where the rigid aromatic mesogen was connected to the middle of the 𝛼,𝜔-unconjugated diene through a flexible spacer.…”