2D conductive nanosheets are central to electronic applications because of their large surface areas and excellent electronic properties. However, tuning the multifunctions and hydrophilicity of conductive nanosheets are still challenging. Herein, a green strategy is developed for fabricating conductive, redox-active, water-soluble nanosheets via the self-assembly of poly(3,4-ethylenedioxythiophene) (PEDOT) on the polydopamine-reduced and sulfonated graphene oxide (PSGO) template. The conductivity and hydrophilicity of nanosheets are highly improved by PSGO. The nanosheets are redox active due to the abundant catechol groups and can be used as versatile nanofillers in developing conductive and adhesive hydrogels. The nanosheets create a mussel-inspired redox environment inside the hydrogel networks and endow the hydrogel with long-term and repeatable adhesiveness. This hydrogel is biocompatible and can be implanted for biosignals detection in vivo. This mussel-inspired strategy for assembling 2D nanosheets can be adapted for producing diverse multifunctional nanomaterials, with various potential applications in bioelectronics.because of their fascinating properties such as large surface areas, numerous active sites, and high conductivity and mechanical strength. [4] In particular, the emerging class of redox-active 2D conductive nanosheets such as covalent organic framework [5] and redox-active heteroatomloaded carbon nanosheets [6] has been used in various areas, e.g., catalysis, solar cells, photochemical water splitting, organic rechargeable battery cathodes, and bioelectronics. The common approach of fabricating conductive nanosheets via mechanical exfoliation lacks effective function tunability. Incorporation of inorganic redox couples such as transition-metal ions has frequently been used to make conductive nanosheets redox active. [7] However, these redox couples often involve toxic and precious-metal ions, and this hinders their biomedical applications. There is therefore an urgent need to develop green and costeffective approaches to fabricating biocompatible, redox-active, and conductive nanosheets for future bioelectronic and biomedical applications.Composites of conductive nanosheets and hydrogels are considered to be promising candidates for use in next-generation soft and flexible bioelectronics. [8] Poly(3,4-ethylenedioxythiophene) (PEDOT) is an ideal conductive material for flexible electronics because of its high electrical conductivity and excellent chemical stability. [9] However, because of the hydrophobicity and intrinsic chemical structure of PEDOT, the production of PEDOT nanosheets and their uniform dispersion in a hydrogel matrix is challenging. In addition, interfacial adhesion between the hydrogel and tissues is of critical importance, especially for electronic skin and implantable bioelectrode. [10] It is desire to develop flexible and tissue-adhesive bioelectronics so that they can tightly integrate with surrounding tissues. Recently, adhesive hydrogels based on mussel-inspired c...

Conductive polymers (CPs) are generally insoluble, and developing hydrophilic CPs is significant to broaden the applications of CPs. In this work, a mussel-inspired strategy was proposed to construct hydrophilic CP nanoparticles (CP NPs), while endowing the CP NPs with redox activity and biocompatibility. This is a universal strategy applicable for a series of CPs, including polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene). The catechol/quinone contained sulfonated lignin (LS) was doped into various CPs to form CP/LS NPs with hydrophilicity, conductivity, and redox activity. These CP/LS NPs were used as versatile nanofillers to prepare the conductive hydrogels with long-term adhesiveness. The CP/LS NPs-incorporated hydrogels have a good conductivity because of the uniform distribution of the hydrophilic NPs in the hydrogel network, forming a well-connected electric path. The hydrogel exhibits long-term adhesiveness, which is attributed to the mussel-inspired dynamic redox balance of catechol/quinone groups on the CP/LS NPs. This conductive and adhesive hydrogel shows good electroactivity and biocompatibility and therefore has broad applications in electrostimulation of tissue regeneration and implantable bioelectronics.

Stretchable and conductive hydrogels are rapidly emerging as new generation candidate for wearable devices. However, the poor electroactivity and bioadhesiveness of traditional conductive hydrogels limited their applications. Herein, a mussel-inspired...

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Abstract-Photovoltaic and photovoltaic heat technology can be coupled by nanofluid-based solar direct absorption thermal collector. It is an important means to improve the efficiency of comprehensive utilization of solar energy. Nanofluids optical theory plays an important role in the development of new photovoltaic-thermal experimental platform. In addition, study on optical characteristics of nanofluids is still in the initial stage. As a result, it is of great significance for the study of the law and mechanism of it. In this paper, the Rayleigh scattering model and the Mie scattering model are used to analyze the critical optical characteristics --transmittances of the nanofluids. Furthermore, the consistency between different theoretical models and experimental datum is studied by contrast verification between experiments and theory calculation. The conclusion shows that Mie scattering model performs better than Rayleigh scattering model and expresses a better applicability in the development of photovoltaic thermal experimental platform. This theoretical study on optical characteristics of nanofluids is expected to prompt on the application of nanotechnology in the field of solar energy. It is also expected to improve the efficiency of comprehensive utilization of solar energy.