One-Pot Synthesis of Melt-Processable Supramolecular Soft Actuators.

The application of reprocessable and reprogrammable soft actuators is limited by the synthetic strategies, 3D-shaping capabilities, and small deformations. In this work, melt-processable supramolecular soft actuators based on segmented copolymers containing thiourethane and liquid crystal segments have been prepared via sequential thiol addition reactions in a one-pot approach using commercially available building blocks. The actuators demonstrated immediate, reversible response and weightlifting capabilities with large deformations up to 32 %. Through exploiting the supramolecular cross-links, the material could be recycled and reprogrammed into 3D actuators and welded into an actuator assembly with different deformation modes. Our work offers a one-pot synthesis and straightforward melt-processable approach to prepare supramolecular soft actuators with large deformations that can be reprocessed and reprogrammed into arbitrary 3D shapes.

CO2 -Induced Morphological Transition of Co-Assemblies from Block-Random Segmented Polymers.

The co-assembly process is an effective approach to construct hierarchically nanostructured soft materials, but morphological transition of co-assemblies upon external stimuli, particularly the "green" trigger CO2 , is not unraveled yet. Here, a segmented copolymer, poly(styrene)-block-poly[(4-vinyl pyridine)-random-((2-(diethylamino)ethyl methacrylate)] (P1), is used to co-assemble in the mixed solvent of dimethyl formamide and water with poly(ethylene oxide)-block-poly[(4-vinyl pyridine)-random-((2-(diethylamino)ethyl methacrylate)] (P2) and poly(ethylene oxide)-block-poly(acrylic acid) (P3), respectively. It is found that Janus micelles are generated from the P1-P2 pair in the presence of ferric ion, while wormlike micelles are formed from the P1-P3 duad. Upon stimulation with CO2 , Janus and wormlike aggregates are transferred into core-shell and spherical micelles, respectively.

Morphological Analysis of Poly(4,4'-oxydiphenylene-pyromellitimide)-Based Organic Solvent Nanofiltration Membranes Formed by the Solution Method.

Poly-(4,4'-oxydiphenylene) pyromellitimide or Kapton is the most widely available polyimide with high chemical and thermal stability. It has great prospects for use as a membrane material for filtering organic media due to its complete insolubility. However, the formation of membranes based on it, at the moment, is an unsolved problem. The study corresponds to the rediscovery of poly(4,4'-oxydiphenylene-pyromellitimide)-based soluble copoly(urethane-imides) as membrane polymers of a new generation. It is shown that the physical structure of PUI films prepared by the solution method becomes porous after the removal of urethane blocks from the polymer, and the pore size varies depending on the conditions of thermolysis and subsequent hydrolysis of the membrane polymer. The film annealed at 170 °C with a low destruction degree of polycaprolactam blocks exhibits the properties of a nanofiltration membrane. It is stable in the aprotic solvent DMF and has a Remasol Brilliant Blue R retention coefficient of 95%. After the hydrolysis of thermally treated films in acidic media, ultrafiltration size 66-82 nm pores appear, which leads to an increase in the permeate flow by more than two orders of magnitude. This circumstance provides opportunities for controlling the membrane polymer structure for further optimization of the performance characteristics of filtration membranes based on it. Thus, we proposed a new preparation method of ultra- and nanofiltration membranes based on poly(4,4'-oxydiphenylene-pyromellitimide) that are stable in aprotic solvents.