Wettability of solids is known to play a critical role in many natural and industrial processes, in particular in the area of life science and nanotechnology. For example, protein adsorption is largely controlled by hydrophobic interactions which greatly depend on the wettability of the surface on which a protein adsorbs. 2,3 The design of a superhydrophobic surface similar to that of a lotus leaf is of special interest in nanotechnology for the development of self-cleaning materials. 4,5 During heavy oil processing, for example, two main challenges, demulsification of water-in-oil emulsions and removal of organic-contaminated solids, are also related to solid surface wettability. The organicrich solids and emulsified water droplets, remaining in oil, are detrimental to downstream upgrading/refining operations and need to be removed from the oil phase. 6,7 Although chemical addition can be used to help break water-in-oil (w/o) emulsions, 8 solids removal usually depends on enhanced mechanical forces by, for example, centrifugation. The difficulty of both the emulsified water droplets and solids removal is magnified by the presence of an extremely viscous, solids-stabilized rag layer in the form of mixed emulsions. 9À12 In our previous study, 1 a biodegradable ethyl cellulose (EC) was found to be an effective demulsifier for breaking water-in-diluted bitumen emulsions. 1,13 The addition of EC to the organic phase was found to cause a significant reduction in diluted bitumenÀwater interfacial tension. Water droplets were shown to flocculate and coalesce in diluted bitumen solutions containing EC, depending on EC concentration. In this study, we investigated the potential of EC as a wettability modifier of solids from oil-wet to water-wet in the context of heavy oil processing. The effect of EC addition on the wettability of asphaltene-or bitumen-contaminated hydrophilic silica and alumina surfaces was determined by contact angle measurements. The mechanism of wettability alteration by EC addition was determined by atomic force microscope (AFM)

BackgroundColon-specific pulsatile drug release, as a combined drug controlled-release model, is a useful drug delivery manner for a series of diseases. New nanomedicines and related preparation methods are highly desired.MethodsWith diclofenac sodium (DS) as a model drug, a new type of structural nanocomposite (SC), in which composite polyvinylpyrrolidone (PVP)–DS core was coated by shellac, was fabricated via modified coaxial electrospinning. For comparison, traditional PVP–DS monolithic hydrophilic nanocomposites (HCs) were generated using a traditional blending process. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), water contact angle (WCA), and in vitro dissolution and ex vivo permeation tests were conducted to characterize the composites.ResultsSEM images demonstrated that both composites were linear nanofibers with smooth surface morphology and cross sections. TEM disclosed that the SCs had a thin shellac sheath layer of approximately 12 nm. XRD and ATR-FTIR results demonstrated that the crystalline DS was converted into amorphous composites with PVP because of favorable secondary interactions. WCA and in vitro dissolution tests demonstrated that the sheath shellac layers in SC could resist acid conditions and provide typical colon-specific pulsatile release, rather than a pulsatile release of HC under acid conditions. Ex vivo permeation results demonstrated that the SCs were able to furnish a tenfold drug permeation rate than the DS particles on the colon membrane.ConclusionA new SC with a shellac coating on hydrophilic amorphous nanocomposites could furnish a colon-specific pulsatile drug release profile. The modified coaxial process can be exploited as a useful tool to create nanocoatings.

A facile low-temperature molten salt approach has been successfully developed to construct MoS2@CoS2 heterostructures for high-efficiency hydrogen evolution reaction.

Chitosan and PEG-based self-healable in situ hydrogel developed as a long-term MRI reporter.

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