Water is vital to the transport of ion through anion exchange membranes (AEMs). However, excessive water causes a decline in stabilities of AEMs. To better understand the water effect on AEMs, two states of water, bulk-like water and non-bulk-like water, were identified quantitatively in perfluorinated anion exchange membrane with seven IEC values in the range of 0.9–1.89 mequiv·g–1. Water in the membranes goes through a redistribution process as IEC changes, where non-bulk-like water content increases almost linearly and steadily with IEC; instead, bulk-like water content increases nonlinearly and sharply with IEC. Bulk-like water has a significant effect on the dimensional stability of the AEMs. It is an advisible strategy to increase IEC value from 0.90 to 1.45 mequiv·g–1 to improve the ion conductivity as well as reasonable dimensional stability of the AEMs.

A soluble perfluorinated polymer poly(tetrafluoroethylene-co-perfluorovinyl ether sulfonamide) (PFSO2NH2) was successfully synthesized and used for preparation of perfluorinated anion exchange membranes (AEMs). PFSO2NH2 is soluble in many solvents and has excellent alkaline stability. The perfluorinated AEM (PFSO2NH–MGMC–OH) which was synthesized by the reaction of PFSO2NH2 with 4-methyl-4-glycidylmorpholin-4-ium chloride (MGMC) exhibits a hydroxide conductivity of 60.4 mS cm−1 at 80 °C and 13.8 mS cm−1 at 30 °C, respectively. The transport numbers of the membrane are 0.91 for Cl− and 0.06 for Na+. The membrane shows good alkaline stability that it maintained 80.1% hydroxide conductivity and 85.6% ion exchange capacity (IEC) values after immersion in 8 M KOH over 30 days at 60 °C. This soluble PFSO2NH2 with high thermal and alkaline stability could be used as a precursor for other perfluorinated functional polymers and membranes.

Block copolymers, dinonylphenyl end-capped polyethylene glycol-b-polystyrene (DNPE-PEO-b-PSs) were synthesized in a one-step atom transfer radical polymerization (ATRP) of styrene. The PEO block in the DNPE-PEO-b-PS samples (volume fraction of PS: 66.8–93.2 %) was found to be amorphous, which contrasts with DNPE-PEO precursor, traditional methoxide end-capped polyethylene glycol-b-polystyrene (PEO-b-PS) and dinonylphenyl end-capped poly-(ethylene glycol)-b-poly(fluorinated methyl methacrylate)(DNPE-PEO-b-PFMAs). Meanwhile, DNPE-PEO-b-PSs display an intriguing self-assembly behavior in solution. Block copolymer particles with mesoporous internal structures are directly formed by self-assembly of DNPE-PEO-b-PS in tetrahydrofuran/water solutions. It is proposed that DNPE end group has an important effect on the crystallization of the block copolymers as well as their self-assembly behaviors in solution.

Perfluorosulfonate ionomer (PFSI) membranes are widely used in electrochemical applications such as fuel cells, chlor-alkali cells, and actuators/sensors. In this work, the surface crystallization of a solution-cast PFSI membrane is quantitatively characterized for the first time by synchrotron grazing incidence X-ray diffraction (GIXRD) and small angle X-ray scattering (GISAXS). A crystallite-rich skin is observed on the PFSI membrane surface, which is 4 nm thick, possesses a crystallinity which is 40% higher than the bulk, with the crystallites aligned parallel to the membrane surface. An intermediate layer exists between the skin and the bulk. The discovery of a crystallite-rich skin may help to explain the surface properties of PFSI membranes, and facilitate an understanding of the transport properties across the membrane interface.

Semicrystalline/fluorinated side-chain crystalline block copolymers, dinonylphenyl end-capped poly(ethylene glycol)-block-poly(fluorinated methyl methacrylate) (DNPEPEO-b-PFMAs), were synthesized by ATRP of 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl methacrylate using a surfactant poly(ethylene glycol) dinonylphenyl ether as precursor. Bulk and thin film morphologies in the block copolymers of DNPEPEO-b-PFMAs were investigated by DSC, WAXS, SAXS, TEM, AFM, and GISAXS. The block copolymers show microphase separated and ordered structures. In the bulk, a cylindrical morphology with PEO cylinders confined in PFMA matrix was confirmed by SAXS and TEM. WAXS studied on the copolymers bulk revealed semicrystalline PEO cylinders and PFMA matrix with the fluorinated side chain organized in bilayers. In thin films of DNPEPEO-b-PFMAs on PDMS modified silicon substrates, well ordered hexagonally packed arrays with PEO cylindrical microdomains normal to the substrate were observed. This fluorinated block polymer with strong unfavorable interaction between two blocks and subsequently hierarchical self-assembly could be a promising material for nanolithography applications.

Polymeric particles with diverse surface and internal hierarchical nanostructures were prepared by the dynamic self-assembly of a fluorine-containing diblock copolymer, poly(tert-butylacrylate)-b-poly(2-[(perfluorononenyl) oxy] ethyl methacrylate) (PtBA-b-PFNEMA) in THF/water mixtures. The surface patterns and internal structures both originated from the microphase separation of PtBA-b-PFNEMA and could be tuned by the preparation conditions. Besides, the interface limitations and geometric confinement of the particles' morphology resulted in the formation of different phase separation structures on the surface and inside the particles. By tuning the water content and preparation temperature, almost parallel cylindrical domains, twisted interconnected cylindrical domains, or spherical domains were obtained on the surface of the particles. Meanwhile, the internal structures of the particles transformed from inner stacked lamella with outer onion-like structures, inner disordered with outer onion-like structures, to bicontinuous structures as the chain mobility and incompatibility of the two blocks could be controlled by the preparation condition. Therefore, the integration of diverse cylindrical surface structures and bicontinuous or onion-like inner structures into hierarchical nanoparticles was achieved.

Co-assembly of poly(tert-butylacrylate)-b-poly(2-[(perfluorononenyl) oxy] ethyl methacrylate) (PtBA-b-PFNEMA, FA) and poly(ethyleneoxide)-b-poly(2-[(perfluorononenyl) oxy] ethyl methacrylate) (PEO-b-PFNEMAs, FB) were carried out to construct binary blend polymeric particles with diverse microphase structures through fluorophilic interaction. Successful control of the phase behavior relies on the location of FB within a nanoscale particle. Due to the fluorophilic interaction, FB is located at the interface between PtBA and PFNEMA or partly dissolved in the PFNEMA phase rather than forming an individual microdomain. By changing the composition of the binary blend particles, the water content, and preparation temperature and the fluorophilic interaction could be tuned and hence the location of FB could be influenced. Order–order phase transition and transformation from most stable onion-like lamellar structures to stacked lamellar structures and cylindrical structures were achieved utilizing PEO113-b-PFNEMA11 (FB1). In addition, the relatively shorter PFNEMA chain and larger dispersity (Đ) of PEO113-b-PFNEMA4 (FB2) resulted in the ubiquitously coexistence of ordered lamellar and gyroid microdomains in the same particles. These transitional structures, which were successfully obtained by both SEM and TEM, would be very useful for the investigation of the phase transition path. The introduction of fluorophilic interactions into the dynamic self-organized precipitation (D-SORP) method sustained the delicate control of the phase behavior in polymeric particles.

Polymeric honeycomb microporous films were prepared from fluorinated diblock copolymers, poly(tert-butyl acrylate)-b-poly(2-[(perfluorononenyl)oxy]ethyl methacrylate) (PtBA-b-PFNEMAs), and four other commercial polymers, including polystyrene (PS), polycarbonate (PC), polylactic acid (PLA), and polymethylmethacrylate (PMMA) via breath figures method. The as-formed fluorinated diblock copolymer micelles in chloroform were not only utilized to stabilize the templated water droplets in bulk, but also introduced as the water droplets stabilizer in other polymeric materials. Our strategy was successfully achieved, as the micropores were decorated with the fluorinated diblock copolymer as directly shown in the SEM images and FT-IR/ATR-FTIR. Polymer concentration and the solution casting volume effects were checked to tune the sizes of the micropores in diblock copolymer films. The ratio of the added fluorinated diblock copolymer as a novel factor to tune the sizes of the micropores was also investigated.