Install the kernel headers and the rtl8188eus driver from the AUR.
The following command will install the linux-headers automatically for all installed kernels:
After the headers and the driver are installed you may need to create a blacklist for the kernel module (if your adapter is not working after rebooting).
Issue the following command to create the blacklist file:
echo 'blacklist 8188eu' | sudo tee /etc/modprobe.d/8188eu-blacklist.conf