Nonequilibrium oscillation fueled by dissipating chemical energy is ubiquitous in living systems for realizing a broad range of complex functions. The design of synthetic materials that can mimic their biological counterparts in the production of dissipative structures and autonomous oscillations is of great interest but remains challenging. Here, a series of environmentally adaptable hydrogels functionalized with photoswitchable spiropyran derivatives that display a tunable equilibrium‐shifting capability, thus endowing those hydrogels with a high degree of freedom and flexibility is reported. Such nonequilibrium hydrogels are able to responsively adapt their shapes under constant light illumination due to asymmetric deswelling, which in turn generates self‐shadowing and consequently creates autonomous self‐oscillating behaviors through a negative feedback process. Diverse oscillation modes including bending, twisting, and snap‐through buckling with tunable frequency and amplitude are widely observed in three different molecular systems. Density functional theory calculations and finite element simulations further demonstrated the robustness of such a photoadaptable self‐oscillation mechanism. This study provides a useful molecular design strategy for construction of highly adaptable hydrogels with potential applications in self‐sustained soft robots and autonomous devices.

Fluorescent end-functional mikto-arm star copolymers were prepared by an “arm-first” approach mediated by a mixture of macro-RAFT agents. RAFT copolymerization of coumarin-POEGMA, boron-dipyrromethene (BODIPY)-PDMA and bisindolylmaleimide (BIM)-PNIPAM with different fluorophore-labeled...

Xanthate-mediated RAFT polymerization has been used to prepare 3-star and 4-star-poly(vinyl chloride) (star-PVC) with a number average molar mass (M n ) in the range of 1 to 7 kg mol −1 . The T g of star-PVC reduces with molar mass and with the number of arms. The star-PVC have substantially lower glasstransition temperatures (T g ) than that of linear PVC of similar M n , with the T g of low-molar mass 4-star-PVC being −7.4 °C. The star-PVC are effective in lowering the T g of blends with commercial PVC when added at 10−30 wt % PVC. When added even at 10 wt %, they are effective in improving the ductility of PVC with an elongation at break (EB) of ∼350% (4-star-PVC) and ∼300% (3star-PVC) relative to commercial PVC, which is substantially higher than that for PVC conventionally plasticized with 30 wt % dioctyl phthalate under similar conditions (EB ∼160%). Importantly, the star-PVC, despite their low molar mass, do not migrate from the PVC blends when tested under standard conditions. The performance of the star-PVC as non-migratory plasticizers for PVC demonstrates the potential for an "all-PVC" flexible PVC.

Switchable reversible addition-fragmentation chain-transfer (RAFT) agents, so-called because they can be reversibly switched by the acid/ base stimulus to offer very good control over polymerization of both “more-activated” monomers (MAMs)...

Precise polymer architecture and self‐assembled morphological control are attractive due to their promising applications, such as drug delivery, biosensors, tissue engineering and “smart” optical systems. Herein, starting from the same hydrophilic units poly(ethylene glycol) (PEG), using CO2‐sensitive monomer N, N‐diethylaminoethyl methacrylate (DEAEMA) and hydrophobic monomer benzyl methacrylate (BzMA), a series of well‐defined statistical, block, and gradient copolymers is designed and synthesized with similar degree of polymerization but different monomer sequences by batch and semi‐batch RAFT polymerization process and their CO2‐responsive behaviors of these nano‐objects is systematically studied. The gradient copolymers are generated by using semi‐batch methods with programmed monomer feed rate controlled by syringe pumps, achieving precise control over desired gradient copolymer composition distribution. In aqueous solution, the copolymers could self‐assemble into various aggregates before CO2 stimulus. Upon bubbling CO2, the gradient copolymers preferred to form nanosheet‐like structures, while the block and statistical copolymers with similar molar mass could only form larger vesicles with thinner membrane thickness or disassemble. The semi‐batch strategy to precisely control over the desired composition distribution of the gradient segment presents an emerging trend for the fabrication and application of stimuli‐responsive polymers.