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Microfluidic devices are important, e.g. in the field of point of care diagnostics. They are of special importance, if they are fabricated out of cheap and renewable materials. Tackling complex separation or sensing problems profits from modular three‐dimensional fluidic devices. Using cotton threads as renewable material allows the modular design of three‐dimensional fluidic devices and networks. Here, fluidic threads with modular designed and tunable thread wettability are presented. The wettability is gradually adjusted from highly hydrophilic to hydrophobic. The thread wettability directly affects the fluid imbibition velocity as well as the distance, which the fluid imbibes into the thread. The wettability adjustment is based on a simple dense or mesoporous silica coating applied onto the cotton thread using sol‐gel chemistry and evaporation induced self‐assembly. In addition to wettability, the mesoporosity and the pore functionalization are used to tune the fluid velocity within the thread. Connecting different silica functionalized threads into one device by knotting them together, fluids can be guided through this network in a predicted manner, which allows a modular design of 3D microfluidic thread‐based devices. [ABSTRACT FROM AUTHOR]

Multistimuli-responsive, in-situ functionalized mesoporous silica films were fabricated by evaporation-induced self-assembly through physical entrapment of the functional template poly(ethylene oxide)- b -poly(2-nitrobenzyl acrylate) (PEO- b -PNBA). The light-cleavable and pH-responsive block copolymer PEO- b -PNBA simultaneously serves as structure-directing agent and for in-situ polymer functionalization of the generated mesopore space. The use of different PEO- b -PNBA compositions results in highly filled hybrid mesoporous silica films with different pore sizes, porosity, and polymer chain sequence within the mesopores. Based on these structural variations and the polymer chain sequence the ionic permselectivity of the silica-polymer hybrid thin films is adjusted. The side chains of the template PNBA block can be deprotected upon irradiation, hereby releasing pH-responsive carboxylic acid groups. The irradiation energy and irradiation time-dependent deprotection allows gradually controlled charge regulation in mesopores. This approach of in-situ functionalization using multistimuli-responsive PEO- b -PNBA block copolymers facilitates the fabrication of multi-responsive hybrid mesoporous silica films and bears high potential for the production of complex, hierarchical, multifunctional mesoporous materials. This fabrication method including direct functionalization of mesoporous structures is of high interest for many applications based on controlled molecular transport in nanoscale pores, such as sensing, separation, or catalysis. [Display omitted] • In-situ functionalization of mesoporous silica films by using PEO- b -PNBA in EISA. • Light- and pH-controlled charge regulation in in-situ functionalized mesopores. • Structure property relation: mesopore order, irradiation, ionic pore accessibility. [ABSTRACT FROM AUTHOR]