@article{wang2024enhancing,

title = {Enhancing the Pressure-Sensitive Electrical Conductance of Self-Assembled Monolayers},

author = {Xintai Wang and Asma Alajmi and Zhangchenyu Wei and Mohammed Alzanbaqi and Naixu Wei and Colin Lambert and Ali Ismael},

url = {https://pubs.acs.org/doi/full/10.1021/acsami.4c15796},

doi = {https://doi.org/10.1021/acsami.4c15796},

year  = {2024},

date = {2024-11-19},

urldate = {2024-01-01},

journal = {ACS Applied Materials & Interfaces},

publisher = {ACS Publications},

abstract = {The inherent large HOMO–LUMO gap of alkyl thiol (CnS) self-assembled monolayers (SAMs) has limited their application in molecular electronics. This work demonstrates significant enhancement of mechano-electrical sensitivity in CnS SAMs by external compression, achieving a gauge factor (GF) of approximately 10 for C10S SAMs. This GF surpasses values reported for conjugated wires and DNA strands, highlighting the potential of CnS SAMs in mechanosensitive devices. Conductive atomic force microscopy (cAFM) investigations reveal a strong dependence of GF on the alkyl chain length in probe/CnS/Au junctions. This dependence arises from the combined influence of molecular tilting and probe penetration, facilitated by the low Young’s modulus of alkyl chains. Theoretical simulations corroborate these findings, demonstrating a shift in the electrode Fermi level toward the molecular resonance region with increasing chain length and compression. Introducing a rigid graphene interlayer prevents probe penetration, resulting in a GF that is largely independent of the alkyl chain length. This highlights the critical role of probe penetration in maximizing mechano-electrical sensitivity. These findings pave the way for incorporating CnS SAMs into mechanosensitive and mechanocontrollable molecular electronic devices, including touch-sensitive electronic skin and advanced sensor technologies. This work demonstrates the potential of tailoring mechanical and electrical properties of SAMs through molecular engineering and interface modifications for optimized performance in specific applications.},

keywords = {AFM, Atomic Force Microscopy, Gauge factor, openQCM, Penetration, QCM, Quartz Crystal Microbalance, Self-Assembled Monolayers (SAMs), Tunnelling decay},

pubstate = {published},

tppubtype = {article}

}

@article{avila2022effects,

title = {Effects of structural and chemical properties of surface coatings on the adsorption characteristics of proteins},

author = {Alejandro Avila-Sierra and Jose A Moreno and Kylee Goode and Taotao Zhu and Peter J Fryer and Alan Taylor and Zhenyu J Zhang},

url = {https://www.sciencedirect.com/science/article/pii/S0257897222009756},

doi = {https://doi.org/10.1016/j.surfcoat.2022.129054},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Surface and Coatings Technology},

pages = {129054},

publisher = {Elsevier},

abstract = {Using Quartz Crystal Microbalance with Dissipation (QCM-D) and Atomic Force Microscopy (AFM), a series of functional surface coatings were investigated to establish the effects of surface structural and chemical properties on the adsorption characteristics of two model proteins, β-Lactoglobulin (β-Lg) and Bovine Serum Albumin (BSA). We show that a free contact scenario, e.g., droplet, that is widely used to evaluate surface energy, is not always equivalent to biofouling conditions where the liquid phase is continuous - releasing the entrapped air from surface geometries could influence the interfacial adsorption process of biomolecules. We observed that surface structuration favoured adsorption of both proteins, especially for the protein of smaller size (β-Lg) as larger amounts of molecules would be required to fill surface geometries. Compact proteinaceous adlayers were observed on the coatings without structure, particularly those containing -CF3 ligands, suggesting stronger adhesion mechanisms due to conformational reorientations of both proteins to facilitate surface binding, especially BSA. In contrast, surface structure led to the formation of soft adlayers as the filling of surface cavities might affect protein conformation and favour protein superposition, hindering removal. We demonstrate how protein-surface binding affinity and packaging density of adsorbed proteins can be modulated as a synergistic effect of surface chemistry and structure, which is of especially importance to the development of anti-fouling coatings.},

key = {Protein adsorption, Functionalized coatings, Structured surfaces, QCM-D, AFM},

keywords = {absorption, AFM, Functionalized coatings, protein, Protein adsorption, QCM-D, Structured surfaces},

pubstate = {published},

tppubtype = {article}

}