Sheng Li

This paper describes a method for fabricating micronozzles using low-temperature wafer-level adhesive bonding with SU-8. The influence of different parameters on the bonding of structured wafers has been investigated. The surface energies of bonded wafers are measured to be in the range of 0.42–0.56 J m−2, which are comparable to those of some directly bonded wafers. Converging–diverging nozzle structures with throat widths as small as 3.6 µm are formed in an SU-8 film bonded with another SU-8 i

Crystallization in polydisperse ethylene–octene multiblock copolymers, polymerized via chain shuttling chemistry, is examined using two-dimensional synchrotron small- and wide-angle X-ray scattering on flow-aligned specimens. The multiblocks are composed of alternating crystalline (hard) blocks of low 1-octene content and amorphous (soft) blocks of high 1-octene content; the block lengths and the number of blocks per chain are characterized by most-probable distributions. These polymers self-ass

Starch based materials are a promising biobased polymer with potential applications in packaging; however the use of these materials has been hampered due to high water absorption. The development of water-resistant coatings for starch-based materials has been an ongoing challenge for starch materials due to poor compatibility between hydrophilic starch and hydrophobic coating. In this work polyethylenimine (PEI) was used to improve the bonding between hydrophilic starch and hydrophobic coatings

The morphologies of polydisperse ethylene−octene diblock copolymers, synthesized via a novel coordinative chain transfer polymerization process, are examined using two-dimensional synchrotron small-angle and wide-angle X-ray scattering on flow-aligned specimens. The diblock copolymers comprise one amorphous block with high 1-octene content and one semicrystalline block with relatively low 1-octene content, and each block ideally exhibits the most-probable distribution. Near-symmetric diblocks wi

The effective development of unconventional tight oil formations, such as Bakken, could include CO2 enhanced oil recovery (EOR) technologies with associated benefits of capturing and storing large quantities of CO2. It is important to conduct the gas injection at miscible condition so as to reach maximum recovery efficiency. Therefore, determination of the minimum miscibility pressure (MMP) of reservoir live oil–injection gas system is critical in a miscible gas flooding project design. In this

Double-crystalline diblock copolymers of linear polyethylene (LPE) and hydrogenated polynorbornene (hPN) are synthesized, and their crystallization behavior and morphology are examined using small-angle (SAXS) and wide-angle X-ray scattering (WAXS). In symmetric hPN/LPE diblocks with molecular weights above 50 kg/mol, the hPN block has previously been shown to crystallize first and set the solid-state microstructure. Two-dimensional WAXS on hand-drawn fiber specimens reveals that the LPE crystal

Micrometer-sized aqueous droplets serve as a unique reactor that drives various chemical reactions not seen in bulk solutions. However, their utilization has been limited to the synthesis of low molecular weight products at low reactant concentrations (nM to μM). Moreover, the nature of chemical reactions occurring outside the droplet remains unknown. This study demonstrated that oil-confined aqueous microdroplets continuously generated hydroxyl radicals near the interface and enabled the synthe

Nucleic acids are a special class of negatively charged polymers, and they can complex with cationic small molecules and polymers to form polyelectrolyte complexes of rich morphology. The initial application focuses on gene delivery and typically involves the complexation of DNA with cationic surfactants and homopolymers. Recent research progress has extended to the complexation of nucleic acids with cationic block copolymers and ionic liquids, leading to the observation of unique morphology and

This paper reports that Cr2O3 hollow nanospheres (HNs) were synthesized via a hydrothermal approach and characterized by scanning electron microscopy, x-ray powder diffraction, transmission electron microscopy (TEM), selective area electron diffraction and high resolution TEM, respectively. In addition, the room-temperature (RT) gas sensing properties of Cr2O3 HNs and conventional powders (CPs) were investigated by means of the surface photovoltage technique. The experimental data demonstrate th

In recent decades, there has been a growing interest in block copolymer with broad dispersity. Previous studies showed that increasing polydispersity influences the self-assembly behavior of block copolymers; however, disagreements between experimental and computational studies remained on key issues including the extent of domain swelling with increasing block dispersity and the effects of polydispersity on order–disorder and order–order transitions in block copolymers. Furthermore, while polyd