In order to give an answer for the challenges of long wavelength-photocontrolled radical polymerization in aqueous solutions and to address the shortcomings of conventional near-infrared (NIR) photocatalysts (PCs) that are difficult to subject to post-treatment, we designed and synthesized a series of β-tetra-substituted water-soluble zinc phthalocyanines (β-TS-Zns) as the NIR PCs for reversible addition–fragmentation chain transfer (RAFT) polymerization successfully under irradiation with NIR (λmax = 730 nm) light at room temperature. Importantly, the NIR PCs can also be designed as polymerizable monomers and covalently loaded on the polymer chains, which are endowed with permanent NIR photocatalysis of the resultant polymers. Moreover, the polymerization can not only be carried out in water but also in phosphate buffer saline (PBS) solution, yielding polymers with controlled molar mass and narrow dispersities (Đ = 1.03–1.25). Therefore, this NIR-photocontrolled aqueous RAFT polymerization system may provide a charming strategy for possible applications in tissue engineering biomaterial in situ benefiting from the high penetration ability of NIR light.

Polymerization-induced self-assembly (PISA) has become an effective strategy to synthesize high solid content polymeric nanoparticles with various morphologies in situ. In this work, one-step PISA was achieved by in situ photocontrolled bromine-iodine transformation reversible-deactivation radical polymerization (hereinafter referred to as Photo-BIT-RDRP). The water-soluble macroinitiator precursor α-bromophenylacetate polyethylene glycol monomethyl ether ester (mPEG1k-BPA) was synthesized in advance, and then the polymer nanomicelles (mPEG1k-b-PBnMA and mPEG1k-b-PHPMA, where BnMA means benzyl methacrylate and HPMA is hydroxypropyl methacrylate) were successfully formed from a PISA process of hydrophobic monomer of BnMA or HPMA under irradiation with blue LED light at room temperature. In addition, the typical living features of the photocontrolled PISA process were confirmed by the linear increase of molecular weights of the resultant amphiphilic block copolymers with monomer conversions and narrow molecular weight distributions (Mw/Mn < 1.20). Importantly, the photocontrolled PISA process is realized by only one-step method by using in situ photo-BIT-RDRP, which avoids the use of transition metal catalysts in the traditional ATRP system, and simplifies the synthesis steps of nanomicelles. This strategy provides a promising pathway to solve the problem of active chain end (C-I) functionality loss in two-step polymerization of BIT-RDRP.

Grafting modification is a useful strategy to endow new functions to fluoropolymers with fluorinated backbone and expand their potential application fields. Herein, we reported a facile method to synthesize graft...

Unimolecular micelles (UIMs) exhibit promising potential in precise diagnosis and accurate treatment of tumor tissues, a pressing problem in the field of medical treatment, because of their perfect stability in...

No abstract

Developing new catalysts with obvious advantages than existing ones is charming but very challenging for near infrared (NIR)photocontrolled reversible-deactivation radical polymerization (RDRP). Herein, a high-efficiency NIR-photocontrolled bromine-iodine transformation RDRP (BIT-RDRP) system was developed by employing persistent radical anions (PRAs) as the catalysts. Specifically, some inherent electron deficient species, such as 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA), can be reduced to PRAs in the presence of common reducing agents (e.g., sodium ascorbate (SA)). Subsequently, the electron-donating PRAs activate the carbon-halogen bonds of dormant species with the help of NIR light and facilitate the formation of carbon-centered radicals (CCRs) to initiate polymerizations. With the assistance of this catalytic system, a monomer conversion of more than 97.0% was achieved within 180−240 min and the polymerization process was still controllable. In addition, several other types of PRA catalysts have also been developed for confirming the catalytic mechanism. All PRAs exhibit highly catalytic ability in the BIT-RDRP system, which opens up a direction for the further development of NIR-photocontrolled RDRP.

No abstract

We report a near-infrared light-responsive hydrogel material consisting of two parts of monomer, ionic liquid monomer (TVBP) and N-isopropylacrylamide (NIPAM), whose crosslinker is a diacrylate containing poly(propylene glycol), all three...