Table 1.

XPS survey data of ppNIPAM (top), spNIPAM (middle), and blank control Si chips (bottom) stored at 25°C low humidity (left), 37°C low (middle) and high humidity (right) conditions before submersion in DPBS for 0 (white), 2 (light grey), or 48 (dark grey) hours. PpNIPAM surfaces remained stable regardless of storage conditions. SpNIPAM surfaces were not stable over time, and the storage conditions affected the final surface composition. Surfaces stored at 25°C were more similar to the theoretical values obtained from the monomer composition by 48 h, where as surfaces stored at 37°C were similar to the control surfaces. N = 9 and the standard deviation was below 5 for each value reported above.

	XPS Survey: Relative Atomic Percent
	25°C Low Humidity				37°C Low Humidity				37°C High Humidity
	C	N	O	Si	C	N	O	Si	C	N	O	Si
Theoretical Composition	75	12.5	12.5	0	75	12.5	12.5	0	75	12.5	12.5	0
ppNIPAM 0hr	78.4	8.7	12.8	0	77.8	11.0	11.2	0	79.4	10.6	9.7	0.2
ppNIPAM 2hr	77.7	8.0	14.4	0	77.9	10.0	12.1	0	79.2	10.7	9.8	0.3
ppNIPAM 48hr	76.0	10.4	13.6	0	75.8	10.3	13.9	0	79.3	10.9	9.7	0.2
spNIPAM 0hr	33.5	5.0	43.3	18.2	37.4	5.6	40.1	16.9	34.7	5.0	41.9	18.3
spNIPAM 2hr	59.3	8.7	23.8	8.2	61.6	9.3	22.5	6.7	58.3	8.7	23.5	9.5
spNIPAM 48hr	28.3	4.1	47.6	20.0	22.8	2.9	52.4	21.9	22.8	2.1	52.1	22.9
Control 0hr	11.0	0	42.3	46.7	11.0	0	42.3	46.7	11.0	0	42.3	46.7
Control 2hr	11.2	0	40.5	48.3	13.8	0	41.6	44.7	13.9	0	43.1	43.1
Control 48hr	15.2	0	52.7	32.1	19.7	0	50.5	29.8	14.9	0	56.1	29.1