Wetting‐Controlled Localized Placement of Surface Functionalities within Nanopores

Abstract

Mimicking such functional control in synthetic nanopores requires precise control of structure and local placement of surface functionality. Such precisely prepared materials with nanoscale control on structure and functionalization would allow, for example, new perspectives in sensing. [1] Further strategies mimicking the functionality of biological channels include dynamic curvature nanochannel-based membranes to regulate ionic transport [2] or flexible elastomer-based microchannels for microfluidic devices. [3] Already today nanoscopically structured materials play a crucial role in applications such as sensors or lab on chip devices, [4] separation, [4d] catalysis, [5] and for the developing of new materials, for example for applications in tissue engineering [6] or for the control of surface wettability. [7] Traditionally, nanostructures are fabricated using top-down approaches like photolithography, ink-jet printing or electrospinning. Alternatively, bottom-up methods, which are based on the self-assembly of molecules or larger building blocks, can yield defined structures with high resolution. [8] Periodic, nanostructured materials are for example accessible through the self-assembly of colloidal building blocks, which can yield macroscopic areas of wellordered colloidal crystals. [9] Such colloidal crystals can be further used as templates to generate inorganic, interconnected nanopore arrays by backfilling with a sol-gel precursor and subsequent removal of the templating particles. [9a,10] In two dimensions, the resulting porous materials are known as inverse colloidal monolayers and their wettability can be adjusted by pore opening angle and surface functionalization. [7e,11] Such structures are ideal model pores due to their uniformity, adjustable pore size and ordered structure.A key step toward multifunctional nanopores with nanolocal control, is the ability to precisely position different functionalities into individual pores. [1a] Therefore, it is necessary to develop strategies for a nanoscale control in manufacturing and functionalization of porous materials. This enables nanopore design with multiple functional and responsive units, individually and precisely placed into each nanopore. [1b] To date, functionalization of porous silica materials is mainly based on postsynthetic functionalization strategies like grafting of silanes from gas or liquid phase or cocondensation of functional building blocks. [12] These approaches generally result in a homogenous functionalization without In the context of sensing and transport control, nanopores play an essential role. Designing multifunctional nanopores and placing multiple surface functionalities with nanoscale precision remains challenging. Interface effects together with a combination of different materials are used to obtain local multifunctionalization of nanoscale pores within a model pore system prepared by colloidal templating. Silica inverse colloidal monolayers are first functionalized with a gold layer to create a hybrid porous ...

Trendbericht: Makromolekulare Chemie

“…Andrieu-Brunsens Gruppe hat durch Steuerung der Oberflächenbenetzung und orthogonale Oberflächenchemie reaktive Polymere selektiv innerhalb der Poren von nanoporösem Silicaoberflächen angebracht. 53) Interessant für die Strukturbildung im Bulk erscheinen auch die Entwicklungen bei In-silico-Simulationen, die dazu beitragen, kinetische Prozesse während der Assemblierung zu verstehen. Dies schreiben etwa Rottler und Müller.…”

Selective Modification of Hierarchical Pores and Surfaces in Nanoporous Materials

“…[ 143,185,186 ] It is not surprising that capillary forces and polarity in nanochannels influence the location of guest species. [ 187 ] This effect was investigated for titania clusters entrapped in the micropores of SBA‐15 silica. Three impregnations with small amounts of titanium isopropoxide in isopropanol were performed, leading to a filling of the microporosity while the mesopores were not affected.…”

Joining host/guest with contrary affinity at the nanoscale by chemical bonds or non-covalent interactions with organic media under diffusion: control of embedded versus exposed magnetite dispersions.

“…In relation, organic media has been effective to control deposition of alike materials as CoO-NP 18 in PS-DVB, functionalization of porous solids with precise nanoscale resolution using individual localized wetting states 19 and, bene cial to impregnate metallic salts in alumina extrudates 15 using glycerol but, when physical a nity is not met at any level, alternative interactions as ones presented here are necessary.…”