Fig. 2: Structure and property of the packaging substrate with module-specific stretchability.

a AFM phase images and structural schematic of pristine SIBS (top) and the SIBS blended with 20% of PIB (bottom). Representative results are presented from n = 5 independently repeated experiments. b Tan δ spectra of pristine SIBS and SIBS/PIB blend films. The glass transition temperature shifted from −34 °C to −39 °C after introducing PIB, suggesting the enhanced chain mobility of SIBS. c Elastic modulus and elongation at break as a function of the PIB content for SIBS/PIB blend films. d Photographs of hard-soft-hard (HSH, i) and soft-hard-soft (SHS, ii) SIBS films before and after being pulled by a 200 g of weight, showing that deformations mainly occurred in the soft regions. H and S represent the hard and soft regions, respectively. e Stress-strain curves of hard, soft, HSH, and SHS films. The inset is a magnified illustration for the region within 100% of strain. Hard and soft refer to the hard SIBS and the soft SIBS, respectively; HSH and SHS refer to the hard-soft-hard SIBS and the soft-hard-soft SIBS, respectively. f Water vapor transmission rate of hard, soft, HSH, SHS, SEBS, and PDMS films measured at 38 °C and 90% relative humidity. The error bars represent standard deviations and data is from n = 3 biologically independent samples and expressed as mean ± s.d. SEBS refers to styrene-ethylene/butylene-styrene and PDMS refers to polydimethylsiloxane; The inset is a cross-section SEM image that shows the seamless transition between the soft region and hard region in HSH and SHS films.