Copper Electroless Metallization of Cellulose Paper via Polydopamine Coating and Silver Catalyst

The paper presents the results of copper electroless metallization of cellulose paper with the use of a polydopamine coating and silver catalyst. The polydopamine coating was deposited via a simple dip method using a dopamine hydrochloride solution in 10 mM TRIS-HCl buffer with a pH of 8.5. The research showed that as a result of this process, cellulose fibers were covered with a homogeneous layer of polydopamine. The unique properties of the polydopamine coating allowed the reduction of silver ions from silver nitrate solution and the deposition of silver atoms on the paper surface. Deposited silver served as a catalyst in the autocatalytic electroless copper-plating process. The copper layer covered the entire surface of the paper sheet after 5 min of metallization, favorably affecting the electrical properties of this material by lowering the surface resistivity. The deposited copper layer was further characterized by good adhesive strength and high susceptibility to deformation.

Simple linear ionic polysiloxane showing unexpected nanostructure and mechanical properties

Polysiloxanes are ubiquitous materials in industry and daily life derived from silicates, an abundant resource. They exhibit various properties, which depend on the main-chain network structure. Linear (1D backbone) polysiloxanes provide amorphous materials. They are recognized as fluid materials in the form of grease or oil with a low glass transition temperature. Herein we report that a simple linear polysiloxane, poly(3-aminopropylmethylsiloxane) hydrochloride, shows an elastic modulus comparable to that of stiff resins such as poly(tetrafluoroethylene). By introducing an ammonium salt at all the units of this polysiloxane, inter- and intramolecular ionic aggregates form, immensely enhancing the elastic modulus. This polysiloxane is highly hygroscopic, and its modulus can be altered reversibly 100 million times between moist and dry atmospheres. In addition, it works as a good adhesive for glass substrates with a shear strength of more than 1 MPa in the dry state. Despite its simple structure with a flexible backbone, this polymer unexpectedly self-assembles to form an ordered lamellar nanostructure in dry conditions. Consequently, this work reveals new functions and possibilities for polysiloxanes materials by densely introducing ionic groups.

Simple Linear Ionic Polysiloxane Showing Unexpected Nanostructure and Mechanical Properties

Polysiloxanes are ubiquitous materials in industry and daily life derived from silicates, an abundant resource. They exhibit various properties, which depend on the main-chain network structure. Linear (1D backbone) polysiloxanes provide amorphous materials. They are recognized as fluid materials in the form of grease or oil with a low glass transition temperature. Herein we report that a simple linear polysiloxane, poly(3-aminopropylmethylsiloxane) hydrochloride, shows an elastic modulus comparable to that of stiff resins such as poly(tetrafluoroethylene). By introducing an ammonium salt at all the units of this polysiloxane, inter- and intramolecular ionic aggregates form, immensely enhancing the elastic modulus. This polysiloxane is highly hygroscopic, and its modulus can be altered reversibly 100 million times between moist and dry atmospheres. In addition, it works as a good adhesive for glass substrates with a shear strength of more than 1 MPa in the dry state. Despite its simple structure with a flexible backbone, this polymer unexpectedly self-assembles to form an ordered lamellar nanostructure in dry conditions. Consequently, this work reveals new functions and possibilities for polysiloxanes materials by densely introducing ionic groups.

Study on the Preparation of High-Temperature Resistant and Electrically Insulating h-BN Coating in Ethanol Solution by Electrophoretic Deposition

A hexagonal boron nitride (h-BN) coating of micron thickness is deposited directly on 316L stainless steel (SS316L) cathode through efficient, adjustable electrophoretic deposition (EPD) in a suspension system containing surfactant and ethanol. It is based on the mixing of h-BN with polyethyleneimine (PEI) resulting in positively charged ceramic powder making cathodic electrophoretic deposition possible. The thickness of the resulting h-BN coatings deposited on SS316L could be controlled by varying the time and the voltage of electrophoretic deposition. The deposition kinetics and mechanism have been discussed. After soaking in Al(H2PO4)3 solution and high-temperature annealing, the h-BN coatings exhibited good adhesive strength. Furthermore, a novel method has been used for the evaluation of the adhesive strength to explore the appropriate experimental conditions. X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to characterize the h-BN coatings. The h-BN coatings are applied for the DC breakdown performance test and exhibit remarkable breakdown voltage and breakdown strength.

Direct N-substituted N-thiocarboxyanhydride polymerization towards polypeptoids bearing unprotected carboxyl groups

Synthesis of poly(α-amino acid)s bearing carboxyl groups is a critical pathway to prepare biomaterials to simulate functional proteins. The traditional approaches call for carboxyl-protected monomers to prevent degradation of monomers or wrong linkage. In this contribution, we synthesize N-carboxypentyl glycine N-thiocarboxyanhydride (CPG-NTA) and iminodiacetic acid N-thiocarboxyanhydride (IDA-NTA) without protection. Initiated by amines, CPG-NTA directly polymerizes into polyCPG bearing unprotected carboxyl groups with controlled molecular weight (2.8–9.3 kg mol−1) and low dispersities (1.08–1.12). Block and random copolymerizations of CPG-NTA with N-ethyl glycine N-thiocarboxyanhydride (NEG-NTA) demonstrate its versatile construction of complicated polypeptoids. On the contrary, IDA-NTA transforms amines into cyclic IDA dimer-capped species with carboxyl end group in decent yields (>89%) regio-selectively. Density functional theory calculation elucidates that IDA repeating unit is prone to cyclize to be the six-membered ring product with low ΔG. The polymer is a good adhesive reagent to various materials with adhesive strength of 33–229 kPa.

Superhydrophobic Polytetrafluoroethylene/Heat-Shrinkable Polyvinyl Chloride Composite Film with Super Anti-Icing Property

Wind power generation is an environmentally friendly way to produce electricity, but wind turbine blades that are prone to freeze in winter will reduce the efficiency of the generator. Therefore, the preparation of anti-icing blades is important and essential. Herein, anti-icing polytetrafluoroethylene (PTFE)/heat-shrinkable polyvinyl chloride (HSPVC) composite film was prepared by depositing a PTFE coating on the surface of HSPVC film via vacuum thermal evaporation. HSPVC films were pretreated respectively by argon and carbon tetrafluoride (CF4) plasma cleaning to introduce new groups and change their surface energy. After that, PTFE coating with a thickness of about 4 μm was deposited on the surface of HSPVC, obtaining a superhydrophobic surface with an apparent water contact angle of 150°. The results demonstrated that the breaking strength of the PTFE/HSPVC composite film using CF4 plasma pretreatment decreased by only 3.47% after exposing to ultraviolet light with the power of 1000 W for 5 min, suggesting an excellent anti-ultraviolet property. Furthermore, compared with the pristine films, the PTFE/HSPVC composite films exhibited better adhesive strength, super anti-icing property even after 10 icing–deicing cycles, and excellent dynamic anti-icing performance. The PTFE/HSPVC composite film with good adhesive strength, anti-ultraviolet, and anti-icing properties has prospective applications in packaging of wind turbine blades.

Features of the Use of Low-Toxic Resins in the Technology of Wood Particle Boards

Source of release of harmful gas of wood particle board (WPB) – formaldehyde is not only free formaldehyde presenting in the formaldehyde resin, but formaldehyde, which is formed from hydroxymethylene groups in a weakly acidic environment during curing the resin during hot pressing of boards. In this, dimethylaniline connections are formed. They are unstable and go into methylene linkages (bridges) with the release of formaldehyde. Currently, with the goal of reducing the discharge formaldehyde from the boards of, low-molal urea-formaldehyde resin is used, mole ratio in which (carbamide (C) : formaldehyde (F) in resins preparing is at the level of (1:1.2 – 1:1.35). Thus we obtain resin with low content of free formaldehyde (0.10-0.15 % by weight of liquid resin). However, it is known that to obtain resins with good adhesive ability, and thus obtaining boards with good physical and mechanical and performance properties, excess of formaldehyde is necessary in its reaction with carbamide. With a relatively small excess of formaldehyde in the starting mixture of urea-formaldehyde we get resins with low reactivity. With increasing quantities of formaldehyde, it is growing vigorously. The highest reactivity corresponds to the mole ratio of carbamide and formaldehyde (C:F) 1:2. When the mole ratio of C:F=1:1 in the synthesis process substances are formed which have no adhesion to the wood. Therefore, the use of low molal resin in wood particleboard technology has not only its positive side (reduced evolution of formaldehyde from plates) but also negative ones (deteriorating physical and mechanical properties of the plates). In this regard for obtaining low-toxic wood particleboard, except for use of low-toxic resins in the technology, it is necessary to apply effective acceptor of formaldehyde. Moreover, it is advisable to use acceptor complex action, which not only linked formaldehyde in the boards, but also improves physical and mechanical and special properties of boards (bio-, water-, atmospheric constancy, etc.).

Highly Reliable Cu Wiring Layer of 1/1 μm Line/Space Using Newly Designed Insulation Barrier Film

The interposer or fan-out packaging technology with ultra-fine line/space has been required in order to achieve high density interconnection between chips with low cost. In this paper, we propose the iBF (insulation barrier film) to satisfy the insulation reliability of 1/1 μm ultra-fine trench wiring. The features of iBF are very low moisture absorptivity less than 0.3%, chloride ion impurities less than 1.0 ppm and high resistance to hydrolysis. In addition, iBF has good adhesive strength to Ti and Cu. The trench wiring was fabricated for mechanical and insulation reliability evaluation using photosensitive dielectric, then covered with iBF. The obtained trench wiring with 2/2, 1.5/1.5 and 1/1 μm line/space has passed the reliability tests such as moisture sensitivity level 2, thermal cycling test and biased HAST (highly accelerated stress test). We have also verified high resolution of photosensitive dielectric and fabrication of ultra-fine trench wiring on iBF to realize fine multi-layer wiring.

NiCo2S4 nanosheet-decorated 3D, porous Ni film@Ni wire electrode materials for all solid-state asymmetric supercapacitor applications

The NiCo2S4 ultra-nanosheet-decorated 3D porous electrode displayed an excellent electrochemical performance due to its porous nature, shorter diffusion path length, good adhesive properties and lower interface contact resistance.

ECOLOGICAL BRITTLE TENSOSENSITIVE COATINGS FOR DEFORMATION AND STRESS RESEARCH

The paper describes a method of preparation and application of «environmentally friendly» brittle tensosensitive coatings on the basis of caramel.It is found that the coating has good adhesive properties, stable tensosensitivity, a simple technology of preparation and application, and is safe for humans and the environment.