AcknowledgmentsThisworkissupportedbytheTataTrusts.

EnhancingtheefficiencyofpesticideapplicationMaherDamak,Seyed RezaMahmoudi,Nasim Hyder,andProf.Kripa VaranasiMassachusettsInstituteofTechnology

AbstractandOpportunityPesticidesareanessentialinputinagriculture.However,theyaretoxicandpollutetheecosystem.Here,wearedevelopinganadditivethatenhancespesticideapplicationefficiency,therebyreducingtheneededquantity.

• Hydrophobicplants(i.e.,wheat,onion,cabbage…)thatrepelsprayedpesticidesarecommon

• Indianfarmerscanrarelyaffordexpensivesprayingequipment(i.e.,electrostaticsprayers)

ProposedSolutionWeaddoppositelychargedpolymerstotwosolutionsoftheliquidandspraythemsimultaneously.

Thesepolymersattractonthesurfaceandformhydrophilicdefectsthatpinthedroplets,therebyenhancingtheliquidretention.

Results• Whendropletscoalesceonthesurface,chargedpolymers

precipitateintosurfacehydrophilicdefects.Thesedefectsexertastronglocalpinningforceonthedropletandpreventitfrombouncing.

• Transitionfrombouncingtostickingindropimpactstranslatesintoamuchhighermacroscopicretentionofsprays.

ValueProposition

• Easy-to-usesolutionwithnobarriertoentry

• Tenfoldincreaseinpesticideretention

• Reductionofproductioncostsandenvironmentalfootprint

ReferencesBergeron,V.,Bonn,D.,Martin,J.Y.&Vovelle,L.Controllingdropletdepositionwithpolymeradditives.Nature 405, 772–775(2000).

DeRutter,H.,Uffing,A.J.,Meinen,E.&Prins,A.Influenceofsurfactantsandplantspeciesonleafretentionofspraysolutions.WeedSci. 567–572(1990).

GenerallyinIndia,noprotectiveequipmentiswornwhensprayingpesticides

Drop-on-dropimpactswithpolyelectrolytes.Thefirstcolumncontainsschematicsoftwopossiblescenarios.Thenextcolumnsaresnapshotsofindividualdropimpactsforeachofthepreviousscenarios.TherightmostcolumncontainsSEMimagesofthesurfaceafterimpact.

Schematicofsimultaneoussprayingofoppositepolyelectrolytes.

Surfacecoverageandretainedvolumeforwaterandoppositepolyelectrolytessprayingonasuperhydrophobicsurface.