Thermal Stability and Orthogonal Functionalization of Organophosphonate Self-Assembled Monolayers as Potential Liners for Cu Interconnect
Ontology highlight
ABSTRACT:
SUBMITTER:
PROVIDER: S-EPMC10601072 | biostudies-literature | 2023 Oct
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:High-density integration technologies with copper (Cu) through-silicon via (TSV) have emerged as viable alternatives for achieving the requisite integration densities for the portable electronics and micro-electro-mechanical systems (MEMSs) package. However, significant thermo-mechanical stresses can be introduced in integrated structures during the manufacturing process due to mismatches of thermal expansion and the mechanical properties between Cu and silicon (Si). The high-density integration demands an interconnection material with a strong mechanical strength and small thermal expansion mismatch. In this study, a novel electroplating method is developed for the synthesis of a graphene-copper (G-Cu) composite with electrochemically exfoliated graphenes. The fabrication and evaluation of the G-Cu composite microstructures, including the microcantilevers and micromirrors supported by the composite, are reported. We evaluated not only the micromechanical properties of the G-Cu composite based on in-situ mechanical resonant frequency measurements using a laser Doppler vibrometer but also the coefficients of thermal expansion (CTE) of the composite based on curvature radius measurements at a temperature range of 20-200 °C. The Young's modulus and shear modulus of the composite are approximately 123 and 51 GPa, which are 1.25 times greater and 1.22 times greater, respectively, than those of pure Cu due to the reinforcement of graphene. The G-Cu composite exhibits a 23% lower CTE than Cu without sacrificing electrical conductivity. These results show that the mechanically strengthened G-Cu composite with reduced thermal expansion is an ideal and reliable interconnection material instead of Cu for complex integration structures.
| S-EPMC6526160 | biostudies-literature
Project description:We examined the surface structure, binding conditions, electrochemical behavior, and thermal stability of self-assembled monolayers (SAMs) on Au(111) formed by N-(2-mercaptoethyl)heptanamide (MEHA) containing an amide group in an inner alkyl chain using scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) to understand the effects of an internal amide group as a function of deposition time. The STM study clearly showed that the structural transitions of MEHA SAMs on Au(111) occurred from the liquid phase to the formation of a closely packed and well-ordered β-phase via a loosely packed α-phase as an intermediate phase, depending on the deposition time. XPS measurements showed that the relative peak intensities of chemisorbed sulfur against Au 4f for MEHA SAMs formed after deposition for 1 min, 10 min, and 1 h were calculated to be 0.0022, 0.0068, and 0.0070, respectively. Based on the STM and XPS results, it is expected that the formation of a well-ordered β-phase is due to an increased adsorption of chemisorbed sulfur and the structural rearrangement of molecular backbones to maximize lateral interactions resulting from a longer deposition period of 1 h. CV measurements showed a significant difference in the electrochemical behavior of MEHA and decanethiol (DT) SAMs as a result of the presence of an internal amide group in the MEHA SAMs. Herein, we report the first high-resolution STM image of well-ordered MEHA SAMs on Au(111) with a (3 × 2√3) superlattice (β-phase). We also found that amide-containing MEHA SAMs were thermally much more stable than DT SAMs due to the formation of internal hydrogen networks in MEHA SAMs. Our molecular-scale STM results provide new insight into the growth process, surface structure, and thermal stability of amide-containing alkanethiols on Au(111).
| S-EPMC9967528 | biostudies-literature
Project description:Aniline-terminated self-assembled monolayers (SAMs) on gold surfaces have successfully reacted with ArSO2NHOSO2Ar (Ar = 4-MeC6H4 or 4-FC6H4) resulting in monolayers with sulfamide moieties and different end groups. Moreover, the sulfamide groups on the SAMs can be hydrolyzed showing the partial regeneration of the aniline surface. SAMs were characterized by water contact angle (WCA) measurements, Fourier-transform infrared reflection absorption spectroscopy (IRRAS) and X-ray photoelectron spectroscopy (XPS).
| S-EPMC5389194 | biostudies-literature
Project description:cGAMP is a signaling molecule produced by the cGAS-DNA complex to establish antimicrobial and antitumor immunity through STING. Whereas STING activation holds potential as a new strategy to treat cancer, cGAMP is generally considered unsuitable for in vivo use because of the rapid cleavage of its phosphodiester linkages and the limited cellular uptake under physiological conditions. Consequently, phosphorothioation and fluorination are commonly used to improve the metabolic stability and permeability of cGAMP and its synthetic analogues. We now show that methylation of the 3'-hydroxyl group of cGAMP also confers metabolic stability and that acylation of the 2'-hydroxyl group can be achieved directly and selectively to enable receptor-mediated intracellular delivery. Unlike phosphorothioation and fluorination, these modifications do not create a new stereogenic center and do not require laborious building block synthesis. As such, orthogonal hydroxyl functionalization is a simple solution to issues associated with the in vivo use of cGAMP.
| S-EPMC10755847 | biostudies-literature
Project description:The majority of current vaccines depend on a continuous "cold chain" of storage and handling between 2 and 8°C. Vaccines experiencing temperature excursions outside this range can suffer from reduced potency. This thermal sensitivity results in significant losses of vaccine material each year and risks the administration of vaccines with diminished protective ability, issues that are heightened in the developing world. Here, using peptide self-assemblies based on the fibril-forming peptide Q11 and containing the epitopes OVA323-339 from ovalbumin or ESAT651-70 from Mycobacterium tuberculosis, the chemical, conformational, and immunological stability of supramolecular peptide materials were investigated. It was expected that these materials would exhibit advantageous thermal stability owing to their adjuvant-free and fully synthetic construction. Neither chemical nor conformational changes were observed for either peptide when stored at 45°C for 7days. ESAT651-70-Q11 was strongly immunogenic whether it was stored as a dry powder or as aqueous nanofibers, showing undiminished immunogenicity even when stored as long as six months at 45°C. This result was in contrast to ESAT651-70 conjugated to a protein carrier and adjuvanted with alum, which demonstrated marked thermal sensitivity in these conditions. Antibody titers and affinities were undiminished in mice for OVA323-339-Q11 if it was stored as assembled nanofibers, yet some diminishment was observed for material stored as a dry powder. The OVA study was done in a different mouse strain and with a different prime/boost regimen, and so it should not be compared directly with the study for the ESAT epitope. This work indicates that peptide self-assemblies can possess attractive thermal stability properties in the context of vaccine development.Statement of significanceAlmost all current vaccines must be maintained within a tight and refrigerated temperature range, usually between 2 and 8°C. This presents significant challenges for their distribution, especially in the developing world. Here we report on the surprisingly robust thermal stability of a self-assembled peptide vaccine. In particular a self-assembled peptide vaccine containing a tuberculosis epitope maintained all of its potency in mice when exposed to an extreme thermal treatment of six months at 45°C. In a different mouse model, we investigated another model epitope and found some storage conditions where potency was diminished. Overall this study illustrates that some self-assembled peptide vaccines can have remarkable thermal stability.
| S-EPMC4821069 | biostudies-literature
Project description:Self-assembled monolayers (SAMs) are widely used to confine proteins and cells to a pattern to study cellular processes and behavior. To fully explore some of these phenomena, it is necessary to control cell growth and confinement for several weeks. Here, we present a simple method by which protein and cellular confinement to a pattern can be maintained for more than 35 days. This represents a significant increase in pattern stability compared to previous monolayer systems and is achieved using an amide-linked glycol monomer on 50 Å titanium/100 Å gold-coated glass coverslips. In addition, this study provides insight into the method of SAM degradation and excludes interfacial mixing of the monomers and blooming of the adlayer as major mechanisms for SAM degradation.
| S-EPMC3295894 | biostudies-literature
Project description:Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.
| S-EPMC4685895 | biostudies-literature
Project description:The rational design of high-temperature endurable Cu-based catalysts is a long-sought goal since they are suffering from significant sintering. Establishing a barrier on the metal surface by the classical strong metal-support interaction (SMSI) is supposed to be an efficient way for immobilizing nanoparticles. However, Cu particles were regarded as impossible to form classical SMSI before irreversible sintering. Herein, we fabricate the SMSI between sputtering reconstructed Cu and flame-made LaTiO2 support at a mild reduction temperature, exhibiting an ultra-stable performance for more than 500 h at 600 °C. The sintering of Cu nanoparticles is effectively suppressed even at as high as 800 °C. The critical factors to success are reconstructing the electronic structure of Cu atoms in parallel with enhancing the support reducibility, which makes them adjustable by sputtering power or decorated supports. This strategy will extremely broaden the applications of Cu-based catalysts at more severe conditions and shed light on establishing SMSI on other metals.
| S-EPMC8664808 | biostudies-literature
Project description:Oxo-graphene nanoribbons (oxo-GNRs) can be prepared by the oxidative unzipping of single-walled carbon nanotubes. We present an orthogonal functionalization method for the functionalization of the rims and the π-surface, respectively, what is only possible due to the high rim portion in oxo-GNRs. In particular, X-ray photoelectron spectroscopy could be used to follow the reaction and detect the marker atoms contained in the addends. We propose that the reported orthogonal functionalization strategy can also be applied on other oxo-functionalized carbon materials, such as graphene quantum dots, or reduced graphene oxide flakes.
| S-EPMC11753386 | biostudies-literature
Project description:Biotherapeutics currently dominate the landscape of new drugs because of their exceptional potency and selectivity. Yet, the intricate molecular structures that give rise to these beneficial qualities also render them unstable in formulation. Hydrogels have shown potential as stabilizing excipients for biotherapeutic drugs, providing protection against harsh thermal conditions experienced during distribution and storage. In this work, we report the utilization of a cellulose-based supramolecular hydrogel formed from polymer-nanoparticle (PNP) interactions to encapsulate and stabilize insulin, an important biotherapeutic used widely to treat diabetes. Encapsulation of insulin in these hydrogels prevents insulin aggregation and maintains insulin bioactivity through stressed aging conditions of elevated temperature and continuous agitation for over 28 days. Further, insulin can be easily recovered by dilution of these hydrogels for administration at the point of care. This supramolecular hydrogel system shows promise as a stabilizing excipient to reduce the cold chain dependence of insulin and other biotherapeutics.
| S-EPMC8441967 | biostudies-literature