Embedding Nanofibres in Fabrics

Low molecular weight gelators (LMWGs) form a network through non-covalent interactions to immobilise solvent and form a gel. Upon drying, the solvent evaporates, leaving behind nanofibres. The main aim of this project was to enhance the filtration properties of a non-woven fabric while minimising impact on the intrinsic air permeability and water vapour permeability. A range of supramolecular nanofibres were investigated, based on 1,3:2,4-dibenzylidene-D-sorbitol (DBS) and compared to N,N’,N”-tris(2-ethylhexyl)-1,3,5-benzenetricarboxamide (BTA) as a benchmark, which has been previously used in the literature in a similar way. Various self-assembled nanostructures have been successfully incorporated into a non-woven fabric including DBS, BTA, DBS-CONHNH2, DBS-SCH3, DBS-OCH3 and small amounts of additives including a DBS dimer, poly(ethylene glycol) and poly(vinyl acetate). The nanoscale morphology was similar for all DBS derivatives. However, BTA gave rise to much larger nanofibres. Non-woven fabrics prepared with DBS, BTA, DBS-SCH3 and a mixture of both DBS and BTA were scaled up and tested for air permeability (AP) and water vapour permeability (WVP). It was found that in most cases, there was a negative correlation between AP and concentration of gelator used to prepare the fabric, although WVP did not appear affected by the presence of nanofibres. The exception was DBS-SCH3 which, at the loadings tested, did not appear to impact on AP. Fabrics prepared with a mixture of DBS and BTA produced a selfsorted network, with three different length-scaled fibres (DBS, BTA and fabric). All the modified fabrics gave AP and WVP results in the range of current protective textiles. Fabrics prepared with DBS and BTA performed very similarly under filtration testing, both in forced conditions and in a more realistic setting. There was some evidence that the smaller DBS nanofibres were physically more robust. Substitution of BTA is thereby possible with a cheap, commercial product, DBS. Under realistic conditions, both gelators enhanced the filtration of a non-woven fabric against aerosols.