Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fabrication of Embedded Microvalve on PMMA Microfluidic Devices through
  Surface Functionalization   The integration of a PDMS membrane within orthogonally placed PMMA
microfluidic channels enables the pneumatic actuation of valves within bonded
PMMA-PDMS-PMMA multilayer devices. Here, surface functionalization of PMMA
substrates via acid catalyzed hydrolysis and air plasma corona treatment were
investigated as possible techniques to permanently bond PMMA microfluidic
channels to PDMS surfaces. FTIR and water contact angle analysis of
functionalized PMMA substrates showed that air plasma corona treatment was most
effective in inducing PMMA hydrophilicity. Subsequent fluidic tests showed that
air plasma modified and bonded PMMA multilayer devices could withstand fluid
pressure at an operational flow rate of 9 mircoliters/min. The pneumatic
actuation of the embedded PDMS membrane was observed through optical microscopy
and an electrical resistance based technique. PDMS membrane actuation occurred
at pneumatic pressures of as low as 10kPa and complete valving occurred at
14kPa for 100 micrometers x 100 micrometers channel cross-sections.

2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph