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The paper describes facile synthesis of boronic ester-containing polycyclosiloxane (pCS-ABPE) through a one-pot-two-step hydrosilylation reaction that allows control of the functionalization efficiency stoichiometrically from zero to 100%. The combination of cyclosiloxane and boronic acid groups is expected to benefit from excellent thermal properties, flexible polymer backbone, and chemical resistance of the polycyclosiloxane part and the dynamic chemical properties of the boronic acid part to generate novel and functional hybrid polymers. Results showed that the hydrolysis of pCS-ABPE gave rise to a boronic-acid-containing polycylcosiloxane (pCS-AB) with good self-assembly nanofilm formation (6 nm film thickness) on plastic substrates through dip-coating method, mainly because of its low surface free energy (∼20 mN m−1). In addition, the dynaminc characteristics of boronic acid groups in the pCS-AB film were demonstrated through water soluble dye Alizarin Red S (ARS) coating. The film surface underwent reversible coating through the boronic acid equilibrium: formation of the dynamic covalent bonding (pCS-AB-ARS) and bond deformation with Zn ions for ARS-Zn complex formation. The performance makes the self-assembly nanofilm promising for chemical sensor applications.

Ferroelectric poly(vinylidene fluoride)/semiconductive polythiophene (P3CPenT) blend monolayers were developed at varying blend ratios using the Langmuir-Blodgett technique. The multilayered blend nanosheets show much improved surface roughness that is more applicable for electronics applications than spin-cast films. Because of the precisely controllable bottom-up construction, semiconductive P3CPenT were well dispersed into the ferroelectric PVDF matrix. Moreover, the ferroelectric matrix contains almost 100% β crystals: a polar crystal phase responsible for the ferroelectricity of PVDF. Both the good dispersion of semiconductive P3CPenT and the outstanding ferroelectricity of the PVDF matrix in the blend nanosheets guaranteed the success of ferroelectric organic non-volatile memories based on ferroelectricity-manipulated resistive switching with a fresh high ON/OFF ratio and long endurance to 30 days.

Ferroelectric poly(vinylidene fluoride) (PVDF) nanofilms have been fabricated by the Langmuir–Blodgett technique, possessing mainly a ferroelectric active phase and a controllable film thickness of 2.3 nm per layer. Atomic force microscopy and Fourier transform infrared spectroscopy were utilized to characterize the film properties. Importantly, the PVDF films could act as barrier layers to prepare spin transport devices using Fe3O4 and Co as bottom and top ferromagnetic electrodes, respectively. Spin-dependent electron transport behaviors were systemically studied in these devices by varying the PVDF film thickness from 3 layers (7 nm) to 13 layers (30 nm). With increasing PVDF layer numbers, the magnetoresistance (MR) response decreases likely due to the change in spin transport from tunneling to hopping transport. We further investigated the MR dependence on operation temperatures (150 K, 200 K, 250 K and 300 K). It is noteworthy that the MR effect was observed even at 300 K with an MR ratio exceeding 2.5%, which is achieved for the first time in such organic devices. The device performance could be further improved at lower operation temperatures. The MR ratios, device resistances and electron transport mechanisms in the present devices were also discussed to analyze the spin transport behaviors. The results indicate that the ferroelectric PVDF nanofilms are promising candidates for spin devices operated at room temperature, thereby shedding light on the design of organic ferroelectric spintronics with a higher performance.

A Cellulose nanofiber (CNF) is an amazing nanomaterial produced from ubiquitous sources with outstanding mechanical, chemical, and barrier properties. This report describes facile functionalization of CNF with trichloro(1H,1H,2H,2H-heptadecafluorodecyl)silane (THFS). The paste form CNF was solvent exchanged from initial water to AK-225 (a mixture of 3,3-dichloro-1,1,1,2,2-pentafluoropropane and 1,3-dichloro-1,1,2,2,3-pentafluoropuropane) before surface modification with THFS. The modified CNFs were dispersed uniformly in AK-225. The CNF film, which was prepared using simple drop casting, showed a superhydrophobic surface with a water contact angle of 160° and oleophilicity with a hexane contact angle of less than 35°. The modified CNF assembly is thermally stable, optically transparent and resistant to corrosive environment (acidic, basic and seawater solutions). The separation of oil and water mixtures was demonstrated using steel mesh coated with modified CNF. Separation efficiency greater than 99% was achieved by simple gravitational force for hydrocarbons and organic solvents. The as-prepared mesh can be used repeatedly more than 50 times with the same efficiency as the initial state.

We fabricated poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE) 75/25 mol% Langmuir–Blodgett (LB) nanofilms by the assistance of amphiphilic poly(N-dodecylacrylamide) (pDDA) nanosheets. The nanosheet is formed based on a well-organized hydrogen bonding network among pDDA amide groups at the air–water interface. By the introduction of the pDDA nanosheet, the film stability of the P(VDF-TrFE) Langmuir film was greatly improved with a twofold increase in the collapse surface pressure to 57 mN m−1 of pure P(VDF-TrFE). Then, the P(VDF-TrFE) Langmuir film was endowed a good transfer ability with a unity transfer ratio irrespective of its non-amphiphilicity. Absorbance of the amide group of pDDA in UV-vis spectra shows a good linear relation with the film thickness. The result indicates that the multilayered film takes a uniform layered structure. The β-crystal content in as-prepared LB nanofilms with no post-treatment is up to 80%, one of the highest values ever reported. The monolayer thickness was determined as 3.5 nm by AFM measurements. The good film properties make the as-prepared P(VDF-TrFE)/pDDA LB ultrathin films (18 nm) available for ferroelectricity measurement using macroscopic methods such as the typical Sawyer–Tower circuit, which is usually challenging for other ultrathin films. The measurements demonstrate improved ferroelectricity, with a high remanent polarization value of 5.0 μC cm−2 at 10 Hz.

Inspired by the marine mussel strategy of adhesion in aqueous environments, catechol-functionalized polysiloxane (CFPS) was synthesized. Facile dip-coating showed good film forming ability on various organic and inorganic substrates with a surface roughness of 4.6 nm (50 μm × 50 μm). Silver nanoparticles (AgNPs) are anchored onto CFPS-modified substrates using a dip coating process. The scanning electron microscopy images revealed that AgNPs were distributed homogeneously on numerous substrates. Moreover, the surface number density and average interspace of the AgNPs were tuned easily by controlling the concentration of AgNP dispersions. A substrate with high-density AgNPs exhibited excellent surface enhanced Raman scattering (SERS) performance with an enhancement factor as high as 7.89 × 107 and an ultra-low detection limitation of 10−10 M, which can be ascribed to the “hotspots” formed between the adjacent AgNPs controlled by CFPS-induced self-assembly. The AgNP structures prepared on different substrates modified using CFPS show a similar high intensity, suggesting a versatile platform of the CFPS film for AgNP assemblies. In addition, AgNPs were anchored to be extremely stable on substrates because of strong hydrogen bonding interactions provided by the high surface-density catechol units of CFPS, which made the substrate a promising SERS sensor for practical applications. In situ SERS detection was also demonstrated on apple peel with no damage to AgNP structures.

As-deposited poly(vinylidene fluoride) (PVDF) Langmuir–Blodgett (LB) nanofilms with a complete β phase show a remarkably high remanent polarization (Pr), about 6.6 μC cm−2 at 81 nm. Extrinsic switching characteristics of the nanofilms are demonstrated. Results also show that highly oriented PVDF homopolymer LB nanofilms down to 12 nm with no post-treatment retain robust room-temperature ferroelectric polarization switching that is greater than 105 operation cycles, with longer standing fatigue endurance than those of PVDF copolymer nanofilms.