A non-diffusive core-shell microcapsule comprising: a) a core comprising, preferably consisting of: - an oil phase; at least one photolabile compound capable of generating, upon exposure to light at a wavelength comprised between 900 and 300 nm, a gas selected among the group consisting of C 2 -C 4 alkenes; wherein the at least one photolabile compound comprises an alkyl aromatic ketone of formula wherein each R 1 represents, independently of each other, a hydrogen atom, a fluorine or chlorine atom, a hydroxyl or amino group or a C 1-2 alkyl, C 1-2 alkoxy, C 1-2 dialkylamino or COR 2' group wherein R 2' represents a hydrogen atom or a C 1-4 alkyl group, provided that at least two R 1 represent a hydrogen atom; or two adjacent R 1, when taken together, represent a OCH 2 O group, a OCH 2 CH 2 O group or a C 3-4 alkanediyl group, optionally substituted with one to four methyl groups; and wherein R 2 represents a propyl, n-butyl or sec-butyl group; and - optionally comprising at least one photo-catalyst; and b) a shell surrounding said core and formed by interfacial polymerization or by a phase separation process induced by polymerization or by coacervation. a) a core comprising, preferably consisting of: - an oil phase; at least one photolabile compound capable of generating, upon exposure to light at a wavelength comprised between 900 and 300 nm, a gas selected among the group consisting of C 2 -C 4 alkenes; wherein the at least one photolabile compound comprises an alkyl aromatic ketone of formula wherein each R 1 represents, independently of each other, a hydrogen atom, a fluorine or chlorine atom, a hydroxyl or amino group or a C 1-2 alkyl, C 1-2 alkoxy, C 1-2 dialkylamino or COR 2' group wherein R 2' represents a hydrogen atom or a C 1-4 alkyl group, provided that at least two R 1 represent a hydrogen atom; or two adjacent R 1, when taken together, represent a OCH 2 O group, a OCH 2 CH 2 O group or a C 3-4 alkanediyl group, optionally substituted with one to four methyl groups; and wherein R 2 represents a propyl, n-butyl or sec-butyl group; and - optionally comprising at least one photo-catalyst; and - an oil phase; at least one photolabile compound capable of generating, upon exposure to light at a wavelength comprised between 900 and 300 nm, a gas selected among the group consisting of C 2 -C 4 alkenes; wherein the at least one photolabile compound comprises an alkyl aromatic ketone of formula wherein each R 1 represents, independently of each other, a hydrogen atom, a fluorine or chlorine atom, a hydroxyl or amino group or a C 1-2 alkyl, C 1-2 alkoxy, C 1-2 dialkylamino or COR 2' group wherein R 2' represents a hydrogen atom or a C 1-4 alkyl group, provided that at least two R 1 represent a hydrogen atom; or two adjacent R 1, when taken together, represent a OCH 2 O group, a OCH 2 CH 2 O group or a C 3-4 alkanediyl group, optionally substituted with one to four methyl groups; and wherein R 2 represents a propyl, n-butyl or sec-butyl group; and - optionally comprising at least one photo-catalyst; and b) a shell surrounding said core and formed by interfacial polymerization or by a phase separation process induced by polymerization or by coacervation.