Functionalizing face masks with natural clays: preliminary results

The materials used in the fabrication of standard, three-layered surgical masks are functionalized by the incorporation of Cuban natural clay with potential microbicidal properties. Different treatments involving aqueous solutions of bentonite (Bent) clay and small amounts of a cationic surfactant are studied. Optical microscopy indicates that the clay particles are effectively adhered to the fibers forming the mask layers. The capacity of the materials to block ballistic droplets showed to be very high for the external and medium layers of a surgical mask both before and after functionalization. However, functionalization demonstrated to increase the blocking capacity of the material in the inner layer, i.e., that closer to the user’s face. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript