Double-shell alginatemicrocapsulescontainingparaffin phasechangematerial(PCM)werepreparedfor
latent heatstoragebyamethodofrepeatedinterfacialcoacervation/crosslinking.Theproposedprocess
consisted ofthreemainsteps:(1)preparationofparaffin containingcoreparticlesbydrippinganO/W
emulsion ofmeltedparaffin andaqueoussodiumalginateintoacalciumchlorideioniccross-linking
solution, (2)encapsulationofthecoreparticlesintodoublealginateshellbyionicgelation/crosslinking
by repeatedinteractionsbetweenthesodiumalginateandcalciumchloridesolutions,and(3)con-
solidation ofthecapsuleshellsbycontactheattreatment.Theeffectsofprocessparameterssuchasthe
sodium alginateconcentration,thecalciumchlorideconcentrationincertainstagesoftheprocess,and
the contacttimebetweentheformedcoreparticlesandthesurroundingalginatesolutionontheparaffin
content andthemeandiameterofcapsuleswerestudiedbyexperimentaldesignandstatisticaleva-
luations. ThepreparedPCMcapsuleshaduniformsizes,core/shellstructure,double-wallednon-porous
alginate coating,tunablevoidspaceinsidethecore,andsuitablyhighparaffin contentatproperly
selected processconditions,correspondingto95.0J/gmeltingand91.7J/gfreezinglatentheatcapacity.
Thermogravimetricanalysisandrepeatedthermalcyclingevidencedgoodthermalstability,andproper
mechanical strengthforleakagefreemicrocapsules.